Chimeric viruses presenting non-native surface proteins and uses thereof

ABSTRACT

The present invention provides chimeric negative-stand RNA viruses that allow a subject, e.g., an avian, to be immunized against two infectious agents by using a single chimeric virus of the invention. In particular, the present invention provides chimeric influenza viruses engineered to express and incorporate into their virions a fusion protein comprising an ectodomain of a protein of an infectious agent and the transmembrane and cytoplasmic domain of an influenza virus protein. Such chimeric viruses induce an immune response against influenza virus and the infectious agent. The present invention also provides chimeric Newcastle Disease viruses (NDV) engineered to express and incorporate into their virions a fusion protein comprising the ectodomain of a protein of an infectious agent and the transmembrane and cytoplasmic domain of an NDV protein. Such chimeric viruses induce an immune response against NDV and the infectious agent.

This application is a divisional of U.S. patent application Ser. No.11/633,130, filed Dec. 1, 2006, which claims priority to U.S.Provisional Application Ser. No. 60/741,833, filed Dec. 2, 2005 and toU.S. Provisional Application Ser. No. 60/802,864, filed May 22, 2006,each of which is incorporated herein by reference in its entirety.

1. FIELD OF THE INVENTION

The present invention provides chimeric negative-stand RNA viruses thatallow a subject, e.g., an avian, to be immunized against two infectiousagents by using a single chimeric virus of the invention. In particular,the present invention provides chimeric influenza viruses engineered toexpress and incorporate into their virions a fusion protein comprisingan ectodomain of a protein of an infectious agent and the transmembraneand cytoplasmic domain of an influenza virus protein. Such chimericviruses induce an immune response against influenza virus and theinfectious agent. The present invention also provides chimeric NewcastleDisease viruses (NDV) engineered to express and incorporate into theirvirions a fusion protein comprising the ectodomain of a protein of aninfectious agent and the transmembrane and cytoplasmic domain of an NDVprotein. Such chimeric viruses induce an immune response against NDV andthe infectious agent.

2. BACKGROUND OF THE INVENTION

A number of DNA viruses have been genetically engineered to direct theexpression of heterologous proteins in host cell systems (e.g., vacciniavirus, baculovirus, etc.). Recently, similar advances have been madewith positive-strand RNA viruses (e.g., poliovirus). The expressionproducts of these constructs, i.e., the heterologous gene product or thechimeric virus which expresses the heterologous gene product, arethought to be potentially useful in vaccine formulations (either subunitor whole virus vaccines). One drawback to the use of viruses such asvaccinia for constructing recombinant or chimeric viruses for use invaccines is the lack of variation in its major epitopes. This lack ofvariability in the viral strains places strict limitations on therepeated use of chimeric vaccinia, in that multiple vaccinations willgenerate host-resistance to the strain so that the inoculated viruscannot infect the host. Inoculation of a resistant individual withchimeric vaccinia will, therefore, not induce immune stimulation.

By contrast, the negative-strand RNA viruses, are attractive candidatesfor constructing chimeric viruses for use in vaccines. Negative-strandRNA viruses, for example, influenza, are desirable because their widegenetic variability allows for the construction of a vast repertoire ofvaccine formulations which stimulate immunity without risk of developinga tolerance.

2.1 Negative-Strand RNA Viruses

The virus families containing enveloped single-stranded RNA of thenegative-sense genome are classified into groups having non-segmentedgenomes (Paramyxoviridae, Rhabdoviridae) or those having segmentedgenomes (Orthomyxoviridae, Bunyaviridae and Arenaviridae). TheParamyxoviridae and Orthomyxoviridae families are described in detailbelow and used in the examples herein. The Paramyxoviridae familycontains the viruses of Newcastle disease Virus (NDV), parainfluenzavirus, Sendai virus, simian virus 5, and mumps virus. TheOrthomyxoviridae family contains the viruses of influenza, types A, Band C viruses, as well as Thogoto and Dhori viruses and infectioussalmon anemia virus.

2.1.1 Influenza Virus

The influenza virions comprise an internal ribonucleoprotein core (ahelical nucleocapsid) containing the single-stranded RNA genome, and anouter lipoprotein envelope lined inside by a matrix protein (M1). Thesegmented genome of influenza A virus consists of eight molecules (sevenfor influenza C) of linear, negative polarity, single-stranded RNAswhich encode ten polypeptides, including: the RNA-dependent RNApolymerase proteins (PB2, PB1 and PA) and nucleoprotein (NP) which formthe nucleocapsid; the matrix membrane proteins (M1, M2); two surfaceglycoproteins which project from the lipid containing envelope:hemagglutinin (HA) and neuraminidase (NA); the nonstructural protein(NS1) and nuclear export protein (NEP). Transcription and replication ofthe genome takes place in the nucleus and assembly occurs via budding onthe plasma membrane. The viruses can reassort genes during mixedinfections.

Influenza virus adsorbs to cells via HA binding activity tosialyloligosaccharides in cell membrane glycoproteins and glycolipids.Following endocytosis of the virion, a conformational change in the HAmolecule occurs within the cellular endosome which facilitates membranefusion, thus triggering uncoating. The nucleocapsid migrates to thenucleus where viral mRNA is transcribed. Viral mRNA is transcribed by aunique mechanism in which viral endonuclease cleaves the capped5′-terminus from cellular heterologous mRNAs which then serve as primersfor transcription of viral RNA templates by the viral transcriptase.Transcripts terminate at sites 15 to 22 bases from the ends of theirtemplates, where oligo(U) sequences act as signals for the addition ofpoly(A) tracts. The viral RNA transcripts then migrate to the cellmembrane and associate with the newly transcribed, transmembrane viralproteins. NA then cleaves sialy residues from the carbohydrate moietiesof membrane bound glycoproteins resulting in encapsulation and cellularrelease of the progeny virus. Of the eight viral RNA molecules soproduced, six are monocistronic messages that are translated directlyinto the proteins representing HA, NA, NP and the viral polymeraseproteins, PB2, PB1 and PA. The other two transcripts undergo splicing,each yielding two mRNAs which are translated in different reading framesto produce M1, M2, NS1 and NEP. In other words, the eight viral RNAsegments code for ten proteins: nine structural and one nonstructural. Asummary of the genes of the influenza virus and their protein productsis shown in Table 1 below.

TABLE 1 INFLUENZA VIRUS GENOME RNA SEGMENTS AND CODING ASSIGNMENTS^(a)Length_(b) Encoded Length_(d) Molecules Segment (Nucleotides)Polypeptide_(c) (Amino Acids) Per Virion Comments 1 2341 PB2 759 30-60RNA transcriptase component; host cell RNA cap binding 2 2341 PB1 75730-60 RNA transcriptase component; initiation of transcription 3 2233 PA716 30-60 RNA transcriptase component 4 1778 HA 566 500 Hemagglutinin;trimer; envelope glycoprotein; mediates attachment to cells 5 1565 NP498 1000 Nucleoprotein; associated with RNA; structural component of RNAtranscriptase 6 1413 NA 454 100 Neuraminidase; tetramer; envelopeglycoprotein 7 1027 M₁ 252 3000 Matrix protein; lines inside of envelopeM₂ 96 ? Structural protein in plasma membrane; spliced mRNA 8 890 NS₁230 Nonstructural protein; NEP 121 ? Nuclear export protein; splicedmRNA ^(a)Adapted from R. A. Lamb and P. W. Choppin (1983), Annual Reviewof Biochemistry, Volume 52, 467-506. _(b)For A/PR/8/34 strain_(c)Determined by biochemical and genetic approaches _(d)Determined bynucleotide sequence analysis and protein sequencing

The pathogenicity of influenza viruses is modulated by multiple virusand host factors. Among the host factors that fight virus infections,the type I interferon (IFNα/β) system represents a powerful antiviralinnate defense mechanism which was established relatively early in theevolution of eukaryotic organisms (Garcia-Sastre, 2002, Microbes Infect4:647-55). The antiviral IFNα/β system involves three major steps: (i)detection of viral infection and IFNα/β secretion, (ii) binding ofIFNα/β to its receptors and transcriptional induction ofIFNα/β-stimulated genes, and (iii) synthesis of antiviral enzymes andproteins. Most viruses, however, have acquired specific geneticinformation encoding IFNα/β antagonist molecules, which effectivelyblock one or more steps of the antiviral IFNα/β system. Influenza Aviruses express a non-structural protein in infected cells, the NS1protein (described in detail, infra), which counteracts the cellularIFNα/β response (Garcia-Sastre et al., 1998, Virology 252:324-30).

2.1.1.1 High-Pathogenenicity Avian Influenza

In recent years, outbreaks of high pathogenic avian influenza (HPAI)have been reported in Asia and Europe (Kawaoka et al., 2005, Natl. Rev.Microbiol. 3:591-600; Koopmans et al., 2004, Lancet 363:587-593).Outbreaks involving influenza A, subtype H5N1 or H7N7 viruses resultedin lethal infections in domestic poultry, and the death of a limitednumber of human cases (Tweed et al., 2004, Emerg. Infec. Dis.10:2196-2199). The current H5N1 viruses have been circulating amongpoultry within China in recent years (Chen et al., 2005, Nature436:191-192), and while migratory birds are considered to be the primaryreservoir of these viruses, transmission from infected poultry back tomigratory birds is believed to have contributed to their increasedgeographical distribution. Currently, the H5N1 virus has emerged fromAsia, spreading across Europe and Africa (Enserink, 2006, Science,311:932). Wholesale culling of poultry has been shown to be a successfulstrategy in eradicating H5N1 outbreaks in Hong Kong in 1997 and theNetherlands in 2003 (Lipatov et al., 2004, J. Virol. 78:8951-8959). Ashuman victims of recent HPAI outbreaks have had close contact withinfected poultry, it follows that the prevention of interspeciestransmission of avian influenza viruses (AIV) may be accomplished by theeradication of AIV in poultry through slaughter. However, for economicand practical reasons, the destruction of infected poultry alone is nolonger considered the method of choice in the control of this disease.In addition, for ethical and ecological reasons, the culling ofmigratory wildfowl is considered an unacceptable practice. Recently, OIE(World Organization for Animal Health) and FAO (Food and AgricultureOrganization of the United Nations) recommended that vaccination ofpoultry should be considered for the control of AIV. In addition, it hasbeen reported that vaccination of chickens with inactivated H5 vaccinewas successful in the interruption of virus transmission in a fieldstudy (Ellis et al., 2004, Avian Pathol. 33:405-412). Recently, Chinahas accepted vaccination as a component of their AIV control program.

The possibility of that the highly pathogenic H5N1 strain can becometransmissible between humans is referenced in terms of a globalpandemic, with the WHO unwilling to estimate the global mortality shouldthe H5N1 virus recombine to human form. Therefore, the need for a methodof management of H5N1 infection in agricultural stocks, from which mosttransmissions to humans are believed to have arisen, is clear.

2.1.2 Newcastle Disease Virus

The Newcastle Disease Virus is an enveloped virus containing a linear,single-strand, nonsegmented, negative sense RNA genome. The genomic RNAcontains genes in the order of 3′-N-P-M-F-HN-L, described in furtherdetail below. The genomic RNA also contains a leader sequence at the 3′end.

The structural elements of the virion include the virus envelope whichis a lipid bilayer derived from the cell plasma membrane. Theglycoprotein, hemagglutinin-neuraminidase (HN) protrudes from theenvelope providing both hemagglutinin (e.g., receptor binding/fusogenic)and neuraminidase activities. The fusion glycoprotein (F), which alsointeracts with the viral membrane, is first produced as an inactiveprecursor, then cleaved post-translationally to produce two disulfidelinked polypeptides. The active F protein is involved in penetration ofNDV into host cells by facilitating fusion of the viral envelope withthe host cell plasma membrane. The matrix protein (M), is involved withviral assembly, and interacts with both the viral membrane as well asthe nucleocapsid proteins.

The main protein subunit of the nucleocapsid is the nucleocapsid protein(N) which confers helical symmetry on the capsid. In association withthe nucleocapsid are the P and L proteins. The phosphoprotein (P), whichis subject to phosphorylation, is thought to play a regulatory role intranscription, and may also be involved in methylation, phosphorylationand polyadenylation. The L gene, which encodes an RNA-dependent RNApolymerase, is required for viral RNA synthesis together with the Pprotein. The L protein, which takes up nearly half of the codingcapacity of the viral genome is the largest of the viral proteins, andplays an important role in both transcription and replication.

The replication of all negative-strand RNA viruses, including NDV, iscomplicated by the absence of cellular machinery required to replicateRNA. Additionally, the negative-strand genome can not be translateddirectly into protein, but must first be transcribed into apositive-strand (mRNA) copy. Therefore, upon entry into a host cell, thevirus can not synthesize the required RNA-dependent RNA polymerase. TheL, P and N proteins must enter the cell along with the genome oninfection.

It is hypothesized that most or all of the viral proteins thattranscribe NDV mRNA also carry out their replication. The mechanism thatregulates the alternative uses (i.e., transcription or replication) ofthe same complement of proteins has not been clearly identified butappears to involve the abundance of free forms of one or more of thenucleocapsid proteins, in particular, the N. Directly followingpenetration of the virus, transcription is initiated by the L proteinusing the negative-sense RNA in the nucleocapsid as a template. ViralRNA synthesis is regulated such that it produces monocistronic mRNAsduring transcription.

Following transcription, virus genome replication is the secondessential event in infection by negative-strand RNA viruses. As withother negative-strand RNA viruses, virus genome replication in Newcastledisease virus (NDV) is mediated by virus-specified proteins. The firstproducts of replicative RNA synthesis are complementary copies (i.e.,plus-polarity) of NDV genome RNA (cRNA). These plus-stranded copies(anti-genomes) differ from the plus-strand mRNA transcripts in thestructure of their termini. Unlike the mRNA transcripts, theanti-genomic cRNAs are not capped and methylated at the 5′ termini, andare not truncated and polyadenylated at the 3′ termini. The cRNAs arecoterminal with their negative strand templates and contain all thegenetic information in each genomic RNA segment in the complementaryform. The cRNAs serve as templates for the synthesis of NDVnegative-strand viral genomes (vRNAs).

Both the NDV negative strand genomes (vRNAs) and antigenomes (cRNAs) areencapsidated by nucleocapsid proteins; the only unencapsidated RNAspecies are virus mRNAs. For NDV, the cytoplasm is the site of virus RNAreplication, just as it is the site for transcription. Assembly of theviral components appears to take place at the host cell plasma membraneand mature virus is released by budding.

2.2 Immunogenic Formulations

Recombinant DNA technology and “reverse genetics” engineering techniquesafford a unique approach to the production of recombinant viruses forthe use in immunogenic formulations. In particular, the presentinvention provides for a method to engineer a negative-strand RNA virussuch that it expresses, or displays, not only native viral antigens, butalso any antigen that may be designed to incorporate into the viralprotein coat. Of particular interest are antigens derived frominfectious organisms other than influenza. In this manner a single virusmay be engineered as an immunogenic compound useful to illicit, activateor induce an immune response which would afford protection against atleast two pathogens. Such a chimeric virus may be further engineeredwhen necessary to modify their virulence, i.e., so that they may beattenuated or further attenuated. Attenuated influenza viruses arebeneficial because they are immunogenic and capable of replication, butnot pathogenic.

Live vaccines are thought to induce improved cross-reactivecell-mediated cytotoxicity as well as a humoral antibody response,providing better protection than inactivated vaccines (Gorse and Belshe,1990, J. Clin. Microbiol. 28:2539-2550; and Gorse et al., 1995, J.Infect. Dis. 172:1-10). Secondly, protective immunity to viral diseasesis likely to involve mucosal IgA response which is not seen withtraditional intramuscularly administered vaccines (Nelson et al., 1998,Vaccine 16:1306-1313). Finally, live vaccines also have the advantage ofintranasal administration which avoids the swelling and muscle sorenessoccasionally associated with the intramuscular administration ofinactivated adjuvanted vaccines. These live vaccines have been reportedto induce not only humoral responses against homotypic influenza virusbut also crossreactive cell-mediated cytotoxicity. Thus, the inventionoffers the potential for the development of new and more effectiveimmune formulations, e.g., vaccine formulations, for the diagnosis,prevention, management or treatment of both viral and non-viralpathogens.

3. SUMMARY OF THE INVENTION

The present invention provides chimeric negative strand RNA virusesengineered to express fusion proteins that incorporate into the virion,methods for producing such chimeric viruses and the use of such viruses,for example as immunogens, in immunogenic formulations, or in in vitroassays. The chimeric viruses of the invention are characterized bydisplaying, on the surface of the virion, not only antigens associatedwith the virus but also the fusion protein.

The present invention provides chimeric influenza viruses and chimericNDVs that allow a subject, e.g., an avian or human, to be immunizedagainst two infectious agents by administering a chimeric influenzavirus or a chimeric NDV. In one aspect, the use of a single virus forinducing an immune response reduces the frequency of administration ofan immunizing formulation. In another aspect, the use of a single virusfor inducing an immune response reduces the cost of immunizing subjects.The lower cost of immunizing subjects increases the likelihood that moresubjects will be able to afford to be immunized and thus, reduces thehealth costs associated with treating subjects suffering from aninfection.

The invention also relates to the use of the chimeric virus of theinvention in compositions (e.g., immunogenic formulations) for humans oranimals. In particular, the chimeric viruses of the invention can beused as vaccines against a broad range of viruses and/or antigens.Because the chimeric virus is engineered to express foreign epitopes inthe virion, compositions (e.g., vaccine formulations) comprising achimeric virus of the invention can be designed for immunization againstmultiple strain variants, different viruses or against completelydifferent infectious agents or disease antigens (e.g., bacteria,parasites, fungi or tumor specific antigens). Many methods may be usedto introduce the live attenuated virus formulations to a human or animalsubject to induce an immune or appropriate cytokine response. Theseinclude, but are not limited to, intranasal, intratrachial, oral,intradermal, intramuscular, intraperitoneal, intravenous andsubcutaneous routes.

The chimeric viruses of the invention enable a subject (e.g. avians) tobe immunized for two infectious diseases by administering the chimericviruses. In a specific embodiment, the chimeric viruses of the inventionenable avians to be immunized for avian influenza virus and NewcastleDisease virus by administering a chimeric virus of the invention. Theavians can be readily immunized by spraying them with the chimeric virusor administering the chimeric virus in an aqueous solution, such as thewater that they drink.

The present invention is based, in part, on Applicants' discovery thatan effective immune response to two infectious agents can be achieved byengineering an influenza virus to express and incorporate into itsvirion a fusion protein comprising the cytoplasmic and transmembranedomains of at least one essential glycoprotein of the virus and theectodomain of a protein of a second infectious agent, wherein the fusionprotein functionally replaces the essential glycoprotein. In one aspect,incorporation of the fusion protein into the virion results in anenhanced immune response to the ectodomain of the second infectiousagent. Engineering the cytoplasmic and transmembrane domains of anessential glycoprotein of the virus into the fusion protein allows thefusion protein to incorporate into the virion. In a particularembodiment, the essential glycoprotein is one or both of the influenzavirus HA and/or NA protein. In another embodiment, the essentialglycoprotein is one or both of the HN or F protein of NDV. Thefunctional replacement of at least one essential glycoprotein of thevirus eliminates the concern about the size limitation of the virusgenome (e.g. the influenza virus genome). In certain embodiments, thefunctional replacement of at least one essential glycoprotein of thevirus with the fusion protein attenuates viral replication in subjects.

The present invention provides a chimeric avian influenza virus,comprising a fusion protein, having (i) an ectodomain of a protectiveantigen of an infectious agent, other than influenza virus fused to (ii)a transmembrane and cytoplasmic domain of a glycoprotein encoded by anessential gene of an influenza virus, wherein the fusion protein isincorporated into an avian influenza virus, in which the function of theessential gene is supplied by the fusion protein or by the glycoproteinnative to the avian influenza virus. In certain embodiments, theessential gene of an influenza virus is a hemagglutinin (HA) gene. Inother embodiments, the essential gene of an influenza virus is aneuraminidase (NA) gene. In certain embodiments, the chimeric avianinfluenza virus is attenuated. In accordance with these embodiments, thechimeric avian influenza virus may be attenuated by mutations in the NS1gene.

The present invention provides a chimeric avian influenza virus,comprising a fusion protein, having (i) an ectodomain of an NDV HNprotein fused to (ii) a transmembrane domain and cytoplasmic domain ofan influenza virus NA protein, wherein the fusion protein isincorporated into an avian influenza virus, in which the function of theNA protein is supplied by the fusion protein or by the glycoproteinnative to the avian influenza virus. In certain embodiments, thechimeric avian influenza virus is attenuated. In accordance with theseembodiments, the chimeric avian influenza virus may be attenuated bymutations in the NS1 gene. In accordance with the invention, any avianinfluenza virus type, subtype or strain may be used.

The present invention provides a chimeric avian influenza virus,comprising a packaged influenza virus NA segment encoding aneuraminidase fusion protein, in which the NA open reading frame ismodified so that the nucleotides encoding the NA ectodomain are replacedby nucleotides encoding an ectodomain of a neuraminidase antigen of aninfectious agent other than influenza that is anchored by theN-terminus, so that the neuraminidase fusion protein is expressed andincorporated into the chimeric avian influenza virus.

The present invention provides a chimeric avian influenza virus,comprising a packaged influenza virus HA segment encoding ahemagglutinin fusion protein, in which the HA open reading frame ismodified so that the nucleotides encoding the HA ectodomain are replacedby nucleotides encoding an ectodomain of a receptor binding/fusogenicantigen of an infectious agent other than influenza virus that isanchored by the C-terminus, so that the hemagglutinin fusion protein isexpressed and incorporated into the chimeric avian influenza virus.

The present invention provides a chimeric avian influenza virus,comprising a packaged bicistronic influenza virus HA segment,comprising: (a) a first open reading frame that encodes an avianinfluenza virus hemagglutinin protein, and (b) a second open readingframe that encodes a hemagglutinin fusion protein, in which thenucleotides encoding the hemagglutinin ectodomain are replaced bynucleotides encoding an ectodomain of a protective antigen of aninfectious agent, other than influenza virus, or encoding a diseaseantigen that is anchored by the C-terminus, so that both the influenzavirus hemagglutinin and the fusion protein are expressed andincorporated into the chimeric avian influenza virus. In certainembodiments, the first open reading frame of the HA segment of thechimeric avian virus is modified to remove the hemagglutinin polybasiccleavage site.

The present invention provides a chimeric avian influenza virus,comprising a packaged bicistronic influenza virus NA segment,comprising: (a) a first open reading frame that encodes an avianinfluenza virus neuraminidase protein, and (b) a second open readingframe that encodes a neuraminidase fusion protein, in which thenucleotides encoding the neuraminidase ectodomain are replaced bynucleotides encoding an ectodomain of a protective antigen of aninfectious agent, other than influenza virus, or encoding a diseaseantigen that is anchored by the N-terminus, so that both the influenzavirus neuraminidase and the fusion protein are expressed andincorporated into the chimeric avian influenza virus. In certainembodiments, the chimeric avian influenza virus comprises an HA segmenthaving an open reading frame modified to remove the hemagglutininpolybasic cleavage site.

The present invention provides a chimeric avian influenza virus,comprising a packaged influenza virus NA segment encoding aneuraminidase fusion protein, in which the NA open reading frame ismodified so that the nucleotides encoding the NA ectodomain are replacedby nucleotides encoding an ectodomain of an HN antigen of NDV, so thatthe neuraminidase fusion protein is expressed and incorporated into thechimeric avian influenza virus. The neuraminidase fusion proteinsupplies the neuraminidase activity for the chimeric avian influenzavirus.

In certain embodiments, a chimeric avian influenza virus of theinvention comprises a packaged NS1 gene segment encoding a modified NS1protein that reduces the cellular interferon antagonist activity of thevirus. Non-limiting examples of mutations in the NS1 gene that result ina modified NS1 protein are provided in Section 5.1.2, infra.

The present invention provides recombinant nucleic acid molecules (e.g.,recombinant DNA molecules) encoding the NA segment of the chimeric avianinfluenza viruses of the invention. The present invention also providesrecombinant nucleic acid molecules (e.g., recombinant DNA molecules)encoding the HA segment of the chimeric avian influenza viruses of theinvention. The present invention further provides recombinant nucleicacid molecules (e.g., recombinant RNA molecules) coding for the NAsegment or the HA segment of the chimeric avian influenza viruses of theinvention.

The present invention provides methods for propagating a chimeric avianinfluenza virus of the invention, comprising culturing the chimericavian influenza virus in an embryonated egg or a cell line that issusceptible to avian influenza virus infection. The present inventionalso provides methods for producing an immunogenic formulation, themethod comprising: (a) propagating a chimeric avian influenza virus ofthe invention in an embryonated egg or a cell line that is susceptibleto avian influenza virus infection; and (b) collecting the progenyvirus, wherein the virus is grown to sufficient quantities and undersufficient conditions that the virus is free from contamination, suchthat the progeny virus is suitable for use in immunogenic formulations,e.g., vaccine formulations.

The present invention provides an attenuated chimeric influenza virus,comprising a fusion protein, having (i) an ectodomain of a protectiveantigen of an infectious agent, other than influenza virus fused to (ii)a transmembrane and cytoplasmic domain of a glycoprotein encoded by anessential gene of an influenza virus, wherein the fusion protein isincorporated into an attenuated influenza virus, in which the functionof the essential gene is supplied by the fusion protein or by theglycoprotein native to the attenuated influenza virus. In certainembodiments, the essential gene of an influenza virus is a hemagglutinin(HA) gene. In other embodiments, the essential gene of an influenzavirus is a neuraminidase (NA) gene. The attenuated chimeric influenzavirus may be any type, subtype or strain of influenza virus. Forexample, the attenuated chimeric influenza virus may be an influenza Avirus, an influenza B virus or an influenza C virus.

The present invention provides an attenuated chimeric influenza virus,comprising a packaged influenza virus NA segment encoding aneuraminidase fusion protein, in which the NA open reading frame ismodified so that the nucleotides encoding the NA ectodomain are replacedby nucleotides encoding an ectodomain of a neuraminidase antigen of aninfectious agent other than influenza that is anchored by theN-terminus, so that the neuraminidase fusion protein is expressed andincorporated into the attenuated chimeric avian influenza virus. Incertain embodiments, the attenuated chimeric influenza virus of theinvention comprises an HA segment having an open reading frame modifiedto remove the hemagglutinin polybasic cleavage site.

The present invention provides an attenuated chimeric influenza virus,comprising a packaged influenza virus HA segment encoding ahemagglutinin fusion protein, in which the HA open reading frame ismodified so that the nucleotides encoding the HA ectodomain are replacedby nucleotides encoding an ectodomain of a hemagglutinin antigen of aninfectious agent other than influenza that is anchored by theC-terminus, so that the hemagglutinin fusion protein is expressed andincorporated into the attenuated chimeric influenza virus.

The present invention provides an attenuated chimeric influenza virus,comprising a packaged bicistronic influenza virus HA segment,comprising: (a) a first open reading frame that encodes an influenzahemagglutinin protein, and (b) a second open reading frame that encodesa hemagglutinin fusion protein, in which the nucleotides encoding thehemagglutinin ectodomain are replaced by nucleotides encoding anectodomain of a protective antigen of an infectious agent, other thaninfluenza, or encoding a disease antigen that is anchored by theC-terminus, so that both the influenza hemagglutinin and the fusionprotein are expressed and incorporated into the attenuated chimericinfluenza virus. In certain embodiments, the first open reading frame ofthe HA segment of the attenuated chimeric influenza virus is modified toremove the hemagglutinin polybasic cleavage site.

The present invention provides an attenuated chimeric influenza virus,comprising a packaged bicistronic influenza virus NA segment,comprising: (a) a first open reading frame that encodes an influenzaneuraminidase protein, and (b) a second open reading frame that encodesa neuraminidase fusion protein, in which the nucleotides encoding theneuraminidase ectodomain are replaced by nucleotides encoding anectodomain of a protective antigen of an infectious agent, other thaninfluenza, or encoding a disease antigen that is anchored by theN-terminus, so that both the influenza neuraminidase and the fusionprotein are expressed and incorporated into the attenuated chimericinfluenza virus. In certain embodiments, the attenuated chimericinfluenza virus of the invention comprises an HA segment having an openreading frame modified to remove the hemagglutinin polybasic cleavagesite.

In certain embodiments, the attenuated chimeric influenza virus of theinvention comprise a packaged NS1 gene segment encoding a modified NS1protein that reduces the cellular interferon antagonist activity of thevirus.

The present invention provides recombinant nucleic acid molecules (e.g.,recombinant DNA molecules) encoding the NA segment of the attenuatedchimeric influenza viruses of the invention. The present invention alsoprovides recombinant nucleic acid molecules (e.g., recombinant DNAmolecules) encoding the HA segment the attenuated chimeric influenzaviruses of the invention. The present invention further providesrecombinant nucleic acid molecules (e.g., recombinant RNA molecules)coding the NA segment or HA segment of the attenuated chimeric influenzaviruses of the invention.

The present invention provides methods for propagating an attenuatedchimeric influenza virus of the invention, comprising culturing theattenuated chimeric influenza virus in an embryonated egg or a cell linethat is susceptible to influenza virus infection. The present inventionalso provides methods for producing an immunogenic formulation, themethod comprising: (a) propagating an attenuated chimeric influenzavirus of the invention in an embryonated egg or a cell line that issusceptible to attenuated influenza virus infection; and (b) collectingthe progeny virus, wherein the virus is grown to sufficient quantitiesand under sufficient conditions that the virus is free fromcontamination, such that the progeny virus is suitable for use inimmunogenic formulations, e.g., vaccine formulations.

The present invention also provides chimeric NDV viruses. In particular,the present invention provides a chimeric NDV, comprising a fusionprotein, having (i) an ectodomain of a protective antigen of aninfectious agent, other than NDV fused to (ii) a transmembrane andcytoplasmic domain of a glycoprotein encoded by an essential gene of anNDV, wherein the fusion protein is incorporated into an NDV, in whichthe function of the essential gene is supplied by the fusion protein orby the glycoprotein native to the NDV. In certain embodiments, theessential NDV gene of NDV is the gene encoding an F protein. In otherembodiments, the essential NDV gene of NDV is the gene encoding an HNprotein. In accordance with the invention, any NDV type, subtype orstrain can be used.

The present invention provides a chimeric NDV, comprising a packagedgenome comprising a nucleotide sequence encoding an F protein-fusionprotein having the transmembrane and cytoplasmic domains of an F proteinand the ectodomain of an antigen of an infectious agent, other than NDV,or a disease antigen that is anchored by the C-terminus, so that the Fprotein-fusion protein is expressed and incorporated into the chimericNDV. In certain embodiments, the genome of the chimeric NDV comprises anucleotide sequence encoding an F protein, so that the F protein isexpressed and incorporated into the chimeric NDV in addition to the NDVF protein-fusion protein. In other embodiments, the nucleotide sequenceencoding the NDV F protein-fusion protein replaces the nucleotidesequence encoding the NDV F protein and the F protein-fusion proteinsupplies the function of the F protein for the chimeric NDV.

The present invention provides a chimeric NDV, comprising a packagedgenome comprising a nucleotide sequence encoding an HN fusion proteinhaving the transmembrane and cytoplasmic domains of an HN protein andthe ectodomain of an antigen of an infectious agent, other than NDV, ora disease antigen that is anchored by the N-terminus, so that the HNfusion protein is expressed and incorporated into the chimeric NDV. Incertain embodiments, the genome of the chimeric NDV comprises anucleotide sequence encoding an HN protein, so that the HN protein isexpressed and incorporated into the chimeric NDV in addition to the NDVHN fusion protein. In other embodiments, the nucleotide sequenceencoding the HN fusion protein replaces the nucleotide sequence encodingthe NDV HN protein and the HN fusion protein supplies the function ofthe HN protein for the chimeric NDV. The present invention providesrecombinant nucleic acid molecules encoding and/or coding the NDV HNprotein or F protein.

The present invention provides methods for propagating a chimeric NDV ofthe invention, comprising culturing the chimeric NDV in an embryonatedegg or a cell line that is susceptible to NDV infection. The presentinvention also provides a method for producing an immunogenicformulation, the method comprising: (a) propagating a chimeric NDV ofthe invention in an embryonated egg or a cell line that is susceptibleto NDV infection; and (b) collecting the progeny virus, wherein thevirus is grown to sufficient quantities and under sufficient conditionsthat the virus is free from contamination, such that the progeny virusis suitable for use in immunogenic formulations, e.g., vaccineformulations.

The present invention provides embryonated eggs comprising the chimericviruses of the invention. The present invention also provides cell linescomprising the chimeric viruses of the invention. The present inventionfurther provides immunogenic formulations comprising the chimericviruses of the invention.

The present invention provides methods of inducing an immune response toone, two or more infectious agents in a subject, the method comprisingadministering an effective amount of a chimeric influenza virus of theinvention. In certain embodiments, the subject is a human subject. Inother embodiments, the subject is a non-human mammal (e.g., a pig,horse, dog, or cat). In yet other embodiments, the subject is an aviansubject. In a specific embodiment, the present invention provides amethod of inducing an immune response to one, two or more infectiousagents in an avian, the method comprising administering an effectiveamount of a chimeric avian influenza virus of the invention.

The present invention provides methods for inducing an immune responseto on, two or more infectious agents in a subject, the method comprisingadministering to the subject an effective amount of a chimeric NDV ofthe invention. In certain embodiments, the subject is a human subject.In other embodiments, the subject is a non-human mammal (e.g., a pig,horse, dog, or cat). In yet other embodiments, the subject is an aviansubject. In a specific embodiment, the present invention providesmethods of inducing an immune response to one, two or more infectiousagents in an avian, the method comprising administering to the avian aneffective amount of a chimeric NDV of the invention.

The present invention provides methods for inducing an immune responseto one, two or more infectious agents in a subject, the methodcomprising administering to the subject an effective amount of anattenuated chimeric influenza virus of the invention. In certainembodiments, the subject is a human subject. In other embodiments, thesubject is a non-human mammal (e.g., a pig, horse, dog, or cat). In yetother embodiments, the subject is an avian subject. In a specificembodiment, the present invention provides methods for inducing animmune response to one, two or more infectious agents in a human, themethod comprising administering to a human in need thereof an effectiveamount of a chimeric virus of the invention.

The present invention provides methods for inducing an immune responseto a disease antigen, the methods comprising administering to thesubject an effective amount of a chimeric virus of the invention. Incertain embodiments the subject is a human. In other embodiments, thesubject is an avian.

3.1 Terminology

As used herein, the term “animal” includes, but is not limited to,companion animals (e.g., dogs and cats), zoo animals, farm animals(e.g., ruminants, non-ruminants, livestock and fowl), wild animals, andlaboratory animals (e.g., rodents, such as rats, mice, and guinea pigs,and rabbits), and animals that are cloned or modified either geneticallyor otherwise (e.g., transgenic animals).

As used herein, the term “about” or “approximately” when used inconjunction with a number refers to any number within 1, 5 or 10% of thereferenced number.

As used herein, the phrase “amino-terminus” of NS1 refers to the aminoacids from the amino terminal amino acid residue (amino acid residue 1)through amino acid residue 115, amino acid residues 1 through 100, aminoacid residues 1 through 75, amino acid residues 1 through 50, amino acidresidues 1 through 25, or amino acid residues 1 through 10 of theinfluenza viral NS1 protein. Deletions from the amino terminus caninclude deletions consisting of 5, preferably 10, 15, 20, 25, 30, 35,40, 45, 50, 55, 60, 65, 70, 73, 75, 80, 85, 90, 95, 99, 100, 105, 110,115, 120, 125, 126, 130, 135, 140, 145, 150, 155, 160, 165, 170 or 175amino acid residues from the amino terminus of NS1

As used herein, the phrase “carboxy-terminus” of NS1 refer to amino acidresidues 116 through the carboxy terminal amino acid residue, amino acidresidues 101 through the carboxy terminal amino acid residue, amino acidresidues 76 through the carboxy terminal amino acid residue, amino acidresidues 51 through the carboxy terminal amino acid residue, or aminoacid residues 26 through the carboxy terminal amino acid residue of theequine influenza viral NS1 protein, when the amino-terminus of NS1 isamino acid residues 1 through amino acid residue 115, amino acidresidues 1 through 100, amino acid residues 1 through 75, amino acidresidues 1 through 50, or amino acid residues 1 through 25,respectively, of an influenza viral NS1 protein. Deletions from thecarboxy terminus can include deletions consisting of 5, preferably 10,15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 73, 75, 80, 85, 90, 95,99, 100, 105, 110, 115, 120, 125, 126, 130, 135, 140, 145, 150, 155,160, 165, 170 or 175 amino acid residues from the carboxy terminus ofNS1.

As used herein, the terms “disease” and “disorder” are usedinterchangeably to refer to a condition in a subject and encompass butare not limited to proliferative disorders (e.g., leukemia, fibrosis,carcinoma (including malignant, non-malignant, metastatic andnon-metastatic carcinomas), and lymphoma), and infections by aninfectious agent (e.g., a virus, bacteria, parasite), or a condition orsymptom associated therewith.

As used herein, the term “epitopes” refers to sites, fragments or aregion of a molecule (e.g., a polypeptide or protein) having antigenicor immunogenic activity in a subject. An epitope having immunogenicactivity is a site, fragment or region of a molecule (e.g., polypeptideor protein) that elicits an antibody response in a subject. An epitopehaving antigenic activity is a site, fragment or region of a molecule towhich an antibody immunospecifically binds as determined by any methodwell-known to one of skill in the art, for example by immunoassays.

As used herein, the term “fragment” in the context of a proteinaceousagent refers to a peptide or polypeptide comprising an amino acidsequence of at least 2 contiguous amino acid residues, at least 5contiguous amino acid residues, at least 10 contiguous amino acidresidues, at least 15 contiguous amino acid residues, at least 20contiguous amino acid residues, at least 25 contiguous amino acidresidues, at least 40 contiguous amino acid residues, at least 50contiguous amino acid residues, at least 60 contiguous amino residues,at least 70 contiguous amino acid residues, at least 80 contiguous aminoacid residues, at least 90 contiguous amino acid residues, at least 100contiguous amino acid residues, at least 125 contiguous amino acidresidues, at least 150 contiguous amino acid residues, at least 175contiguous amino acid residues, at least 200 contiguous amino acidresidues, or at least 250 contiguous amino acid residues of the aminoacid sequence of a peptide, polypeptide or protein. In one embodiment, afragment of a full-length protein retains activity of the full-lengthprotein. In another embodiment, the fragment of the full-length proteindoes not retain the activity of the full-length protein.

As used herein, the term “fragment” in the context of a nucleic acidencoding a polypeptide or protein refers to a nucleic acid comprising annucleic acid sequence of at least 2 contiguous nucleotides, at least 5contiguous nucleotides, at least 10 contiguous nucleotides, at least 15contiguous nucleotides, at least 20 contiguous nucleotides, at least 25contiguous nucleotides, at least 30 contiguous nucleotides, at least 35contiguous nucleotides, at least 40 contiguous nucleotides, at least 50contiguous nucleotides, at least 60 contiguous nucleotides, at least 70contiguous nucleotides, at least contiguous 80 nucleotides, at least 90contiguous nucleotides, at least 100 contiguous nucleotides, at least125 contiguous nucleotides, at least 150 contiguous nucleotides, atleast 175 contiguous nucleotides, at least 200 contiguous nucleotides,at least 250 contiguous nucleotides, at least 300 contiguousnucleotides, at least 350 contiguous nucleotides, or at least 380contiguous nucleotides of the nucleic acid sequence encoding a peptide,polypeptide or protein. In a preferred embodiment, a fragment of anucleic acid encodes a peptide or polypeptide that retains activity ofthe full-length protein. In another embodiment, the fragment of thefull-length protein does not retain the activity of the full-lengthprotein.

The term “heterologous sequence” as used herein in the context of aproteinaceous agent refers to a molecule that is not found in nature tobe associated with the chimeric virus backbone or, in particular, thechimeric virus glycoprotein. The term “heterologous sequence” in thecontext of a nucleic acid sequence or nucleic acid molecule refers to amolecule that is not found in nature to be associated with the genome ofthe chimeric virus backbone.

The term “immunospecifically binds an antigen” and analogous terms asused herein refer to molecules that specifically bind to an antigen anddo not specifically bind to another molecule (e.g., antigen specificantibodies including both modified antibodies (i.e., antibodies thatcomprise a modified IgG (e.g., IgG1) constant domain, or FcRn-bindingfragment thereof (e.g., the Fc-domain or hinge-Fc domain)) andunmodified antibodies (i.e., antibodies that do not comprise a modifiedIgG (e.g., IgG1) constant domain, or FcRn-binding fragment thereof(e.g., the Fc-domain or hinge-Fc domain)). Molecules that specificallybind one antigen may be cross-reactive with related antigens.Preferably, a molecule that specifically binds one antigen does notcross-react with other antigens. A molecule that specifically binds anantigen can be identified, for example, by immunoassays, BIAcore, orother techniques known to those of skill in the art. A moleculespecifically binds an antigen when it binds to said antigen with higheraffinity than to any cross-reactive antigen as determined usingexperimental techniques, such as radioimmunoassays (MA) andenzyme-linked immunosorbent assays (ELISAs). See, e.g., Paul, ed., 1989,Fundamental Immunology Second Edition, Raven Press, New York at pages332-336 for a discussion regarding antibody specificity.

As used herein, the term “in combination” in the context of theadministration of (a) therapy(ies) to a subject, refers to the use ofmore than one therapy (e.g., more than one prophylactic agent and/ortherapeutic agent). The use of the term “in combination” does notrestrict the order in which therapies (e.g., prophylactic and/ortherapeutic agents) are administered to a subject (e.g., a subject withan influenza virus infection, and NDV infection, or a condition orsymptom associated therewith, or a subject with another infection (e.g.,another viral infection)). A first therapy (e.g., a first prophylacticor therapeutic agent) can be administered prior to (e.g., 5 minutes, 15minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 4 hours, 6 hours, 12hours, 24 hours, 48 hours, 72 hours, 96 hours, 1 week, 2 weeks, 3 weeks,4 weeks, 5 weeks, 6 weeks, 8 weeks, or 12 weeks before), concomitantlywith, or subsequent to (e.g., 5 minutes, 15 minutes, 30 minutes, 45minutes, 1 hour, 2 hours, 4 hours, 6 hours, 12 hours, 24 hours, 48hours, 72 hours, 96 hours, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6weeks, 8 weeks, or 12 weeks after) the administration of a secondtherapy (e.g., a second prophylactic or therapeutic agent) to a subject(e.g., a subject with an influenza virus infection, an NDV infection ora condition or symptom associated therewith, or another infection (e.g.,another viral infection)).

As used herein, the phrase “interferon antagonist activity” of aproteinaceous agent refers to a protein or polypeptide, or fragment,derivative, or analog thereof that reduces or inhibits the cellularinterferon immune response. In particular, a protein or polypeptide, orfragment, derivative, or analog thereof (e.g., influenza virus NS1) thathas interferon antagonist activity reduces or inhibits interferonexpression and/or activity. In a specific embodiment, the phrase“interferon antagonist activity” refers to virus protein or polypeptide,or fragment, derivative, or analog thereof (e.g. an influenza virusprotein) that reduces or inhibits the cellular interferon immuneresponse. A viral protein or polypeptide with interferon antagonistactivity may preferentially affect the expression and/or activity of oneor two types of interferon (IFN). In one embodiment, the expressionand/or activity of IFN-α is affected. In another embodiment, theexpression and/or activity of IFN-β is affected. In another specificembodiment, the expression and/or activity of IFN-γ is affected. Incertain embodiments, the expression and/or activity of IFN-α, IFN-βand/or IFN-γ in an embryonated egg or cell is reduced approximately 1 toapproximately 100 fold, approximately 5 to □ approximately 80 fold,approximately 20 to approximately 80 fold, approximately 1 toapproximately 10 fold, approximately 1 to approximately 5 fold,approximately 40 to approximately 80 fold, or 1, 2, 3, 4, 5, 7, 10, 15,20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100fold by a proteinaceous agent with interferon antagonist activityrelative to the expression and/or activity of IFN-α, IFN-β, and/or IFN-γin a control embryonated egg or a cell not expressing or not contactedwith such a proteinaceous agent as measured by the techniques describedherein or known to one skilled in the art.

As used herein, the phrases “IFN deficient systems” or “IFN-deficientsubstrates” refer to systems, e.g., cells, cell lines and animals, suchas mice, chickens, turkeys, rabbits, rats, horses etc., which do notproduce one, two or more types of IFN, or do not produce any type ofIFN, or produce low levels of one, two or more types of IFN, or producelow levels of any IFN (i.e., a reduction in any IFN expression of 5-10%,10-20%, 20-30%, 30-40%, 40-50%, 50-60%, 60-70%, 70-80%, 80-90% or morewhen compared to IFN-competent systems under the same conditions), donot respond or respond less efficiently to one, two or more types ofIFN, or do not respond to any type of IFN, and/or are deficient in theactivity of antiviral genes induced by one, two or more types of IFN, orinduced by any type of IFN.

As used herein, the terms “infection”, “influenza infection”, “avianinfluenza infection” and “NDV infection” refer to all stages of aninfluenza virus', an avian influenza virus', a NDV's, or anotherinfectious agent's (e.g., another viral or a bacterial infection) lifecycle in a subject (including, but not limited to the invasion by andreplication of influenza virus, avian influenza virus, NDV or otherinfectious agent in a cell or body tissue), as well as the pathologicalstate resulting from the invasion by and replication of influenza virus,avian influenza virus or NDV. The invasion by and multiplication of aninfluenza virus, avian influenza virus, NDV or other infectious agentincludes, but is not limited to, the following steps: the docking of theviruses (e.g., influenza virus, avian influenza virus or NDV particle)to a cell, fusion of a virus with a cell membrane, the introduction ofviral genetic information into a cell, the expression of viral proteins(e.g., influenza virus, avian influenza virus or NDV proteins), theproduction of new viral particles (i.e., influenza virus, avianinfluenza virus or NDV particles) and the release of the virus (e.g.,influenza virus, avian influenza virus or NDV particles) from a cell. Arespiratory infection (e.g., an influenza virus or NDV infection) may bean upper respiratory tract infection (URI), a lower respiratory tractinfection (LRT), or a combination thereof. In specific embodiments, theinfection is a secondary infection (e.g. secondary pneumonia) whichmanifests after the onset of primary infection (e.g. viral pneumonia).Secondary infections arise due to the primary infection or a symptom orcondition associated therewith predisposing the infected subject to sucha secondary infection. In specific embodiments, the pathological stateresulting from the invasion by and replication of an influenza virus,avian influenza virus or NDV is an acute influenza virus, avianinfluenza virus or NDV disease. Acute stages of the respiratoryinfections can manifest as pneumonia and/or bronchiolitis, where suchsymptoms may include hypoxia, apnea, respiratory distress, rapidbreathing, wheezing, cyanosis, etc. The acute stage of the respiratoryinfections (e.g., influenza virus and NDV infections) requires anaffected individual to obtain medical intervention, such ashospitalization, administration of oxygen, intubation and/orventilation.

As used herein, the term “isolated”, in the context of viruses, refersto a virus that is derived from a single parental virus. A virus can beisolated using routine methods known to one of skill in the artincluding, but not limited to, those based on plaque purification andlimiting dilution.

As used herein, the term “isolated” in the context of nucleic acidmolecules refers to a nucleic acid molecule which is separated fromother nucleic acid molecules which are present in the natural source ofthe nucleic acid molecule. Moreover, an “isolated” nucleic acidmolecule, such as a cDNA molecule, can be substantially free of othercellular material, or culture medium when produced by recombinanttechniques, or substantially free of chemical precursors or otherchemicals when chemically synthesized. In a preferred embodiment, anucleic acid molecule encoding a viral protein is isolated.

As used herein, the terms “manage,” “managing,” and “management” referto the beneficial effects that a subject derives from a therapy (e.g., aprophylactic or therapeutic agent), which does not result in a cure ofthe disease (e.g. infection). In certain embodiments, a subject isadministered one or more therapies (e.g., prophylactic or therapeuticagents, such as an antibody of the invention) to “manage” an influenzavirus infection, avian influenza virus or NDV infection or an infectionwith another infectious agent, one or more symptoms thereof, or acondition associated with, potentiated by, or potentiating an influenzavirus infection or NDV infection or infection with another infectiousagent, so as to prevent the progression or worsening of the infection.

As used herein, the phrase “multiplicity of infection” or “MOI” is theaverage number of virus per infected cell. The MOI is determined bydividing the number of virus added (ml added×Pfu) by the number of cellsadded (ml added×cells/ml).

As used herein, the phrase “NS1 gene” refers to the gene which encodesthe nonstructural protein (NS1) in influenza. NS1 is one of the eightmolecules encoded by the segmented genome of influenza A and otherviruses. An “NS1 gene product” refers to a gene product (e.g., a RNA orprotein) encoded by an NS1 gene. In the case of a protein, the NS1 geneproduct is full-length and has wild-type NS1 activity (e.g., from strainA/WSN/33).

As used herein, the terms “nucleic acids,” “nucleotide sequences” and“nucleic acid molecules” include DNA molecules (e.g., cDNA or genomicDNA), RNA molecules (e.g., mRNA), combinations of DNA and RNA moleculesor hybrid DNA/RNA molecules, and analogs of DNA or RNA molecules. Suchanalogs can be generated using, for example, nucleotide analogs, whichinclude, but are not limited to, inosine or tritylated bases. Suchanalogs can also comprise DNA or RNA molecules comprising modifiedbackbones that lend beneficial attributes to the molecules such as, forexample, nuclease resistance or an increased ability to cross cellularmembranes. The nucleic acids or nucleotide sequences can besingle-stranded, double-stranded, may contain both single-stranded anddouble-stranded portions, and may contain triple-stranded portions, butpreferably is double-stranded DNA.

As used herein, the terms “prevent”, “preventing” and “prevention” referto the prevention of the recurrence or onset of, or a reduction in oneor more symptoms of a disease (e.g., viral infection or other infectiousdisease) in a subject as result of the administration of a therapy(e.g., a prophylactic or therapeutic agent). For example, in the contextof the administration of a therapy to a subject for an infection,“prevent”, “preventing” and “prevention” refer to the inhibition or areduction in the development or onset of an infection (e.g, an influenzavirus infection, an NDV infection or a condition associated therewith oran infection other than an influenza virus or NDV infection or acondition associated therewith), or the prevention of the recurrence,onset, or development of one or more symptoms of an infection (e.g., aninfluenza virus infection, an NDV infection or a condition associatedtherewith or an infection other than an influenza virus infection, anNDV infection or a condition associated therewith), in a subjectresulting from the administration of a therapy (e.g., a prophylactic ortherapeutic agent), or the administration of a combination of therapies(e.g., a combination of prophylactic or therapeutic agents).

As used herein, the term “protective antigen” in the context of aninfectious agent includes any molecule which is capable of eliciting aprotective immune response when administered to a subject, which immuneresponse is directed against the infectious agent.

As used herein, the terms “prophylactic agent” and “prophylactic agents”refer to any agent(s) which can be used in the prevention of a disease(e.g., an infection) or a symptom thereof (e.g., an influenza virusinfection, an NDV infection or a condition or symptom associatedtherewith, or an infection other than an influenza virus of an NDVinfection or a condition or symptom associated therewith). Preferably, aprophylactic agent is an agent which is known to be useful to, has beenor is currently being used to the prevent or impede the onset,development, progression and/or severity of a disease or a symptomthereof (e.g. an infection or a condition or a symptom associatedtherewith).

As used herein, the phrase “purified” in the context of viruses refersto a virus which is substantially free of cellular material and culturemedia from the cell or tissue source from which the virus is derived.The language “substantially free of cellular material” includespreparations of virus in which the virus is separated from cellularcomponents of the cells from which it is isolated or recombinantlyproduced. Thus, virus that is substantially free of cellular materialincludes preparations of protein having less than about 30%, 20%, 10%,or 5% (by dry weight) of cellular protein (also referred to herein as a“contaminating protein”). The virus is also substantially free ofculture medium, i.e., culture medium represents less than about 20%,10%, or 5% of the volume of the virus preparation. A virus can bepurified using routine methods known to one of skill in the artincluding, but not limited to, chromatography and centrifugation.

As used herein, the terms “subject” or “patient” are usedinterchangeably. As used herein, the terms “subject” and “subjects”refers to an animal (e.g., avians, reptiles, and mammals). In someembodiments, the subject is a mammal including a non-primate (e.g., acamel, donkey, zebra, cow, horse, horse, cat, dog, rat, and mouse) and aprimate (e.g., a monkey, chimpanzee, and a human). In some embodiments,the subject is a non-human mammal. In other embodiments the subject is ahuman. In certain embodiments, the mammal (e.g., human) is 0 to 6 monthsold, 6 to 12 months old, 1 to 5 years old, 5 to 10 years old, 10 to 15years old, 15 to 20 years old, 20 to 25 years old, 25 to 30 years old,30 to 35 years old, 35 to 40 years old, 40 to 45 years old, 45 to 50years old, 50 to 55 years old, 55 to 60 years old, 60 to 65 years old,65 to 70 years old, 70 to 75 years old, 75 to 80 years old, 80 to 85years old, 85 to 90 years old, 90 to 95 years old or 95 to 100 yearsold. In a specific embodiment, the subject or patient is an avian. Incertain embodiments, the avian is 0 to 3 months old, 3 to 6 months old,6 to 9 months old, 9 to 12 months old, 12 to 15 months old, 15 to 18months old, or 18 to 24 months old.

As used herein, the term “synergistic” in the context of theadministration or the result or therapies, refers to a combination oftherapies (e.g., prophylactic or therapeutic agents) which is moreeffective than the additive effects of any two or more single therapies(e.g., one or more prophylactic or therapeutic agents). A synergisticeffect of a combination of therapies (e.g., a combination ofprophylactic or therapeutic agents) permits the use of lower dosages ofone or more of therapies (e.g., one or more prophylactic or therapeuticagents) and/or less frequent administration of said therapies to asubject with a disease (e.g., an influenza virus infection, an NDVinfection or a condition or symptom associated therewith, or aninfection other than an influenza virus infection, NDV infection or acondition or symptom associated therewith). The ability to utilize lowerdosages of therapies (e.g., prophylactic or therapeutic agents) and/orto administer said therapies less frequently reduces the toxicityassociated with the administration of said therapies to a subjectwithout reducing the efficacy of said therapies in the prevention ortreatment of a disease (e.g., an influenza virus infection or acondition or symptom associated therewith, or an infection other than aninfluenza virus infection, NDV infection or a condition or symptomassociated therewith). In addition, a synergistic effect can result inimproved efficacy of therapies (e.g., prophylactic or therapeuticagents) in the prevention, management or treatment of a disease (e.g.,an influenza virus infection, an NDV infection or a condition orsymptoms associated therewith, or an infection other than an influenzavirus infection, an NDV infection or a condition or symptom associatedtherewith). Finally, synergistic effect of a combination of therapies(e.g., prophylactic or therapeutic agents) may avoid or reduce adverseor unwanted side effects associated with the use of any single therapy.

As used herein, the terms “therapies” and “therapy” can refer to anyprotocol(s), method(s), and/or agent(s) that can be used in theprevention, treatment, management, or amelioration of a disease (e.g.,cancer, an influenza virus infection, an NDV infection or a condition orsymptom associated therewith, or an infection other than an influenzavirus infection, or NDV infection or a condition or symptom associatedtherewith). In certain embodiments, the terms “therapies” and “therapy”refer to biological therapy, supportive therapy, and/or other therapiesuseful in treatment, management, prevention, or amelioration of adisease, an infection or a condition or symptom associated therewith,known to one of skill in the art.

As used herein, the terms “therapeutic agent” and “therapeutic agents”refer to any agent(s) which can be used in the prevention, treatment,management, or amelioration of a disease (e.g. an infection or a symptomthereof (e.g., an influenza infection, an NDV infection or a conditionor symptoms associated therewith, an infection other than an influenzavirus infection, NDV infection or a condition or symptom associatedtherewith)). Preferably, a therapeutic agent is an agent which is knownto be useful for, or has been or is currently being used for theprevention, treatment, management, or amelioration of a disease orsymptom associated therewith (e.g., an influenza infection, NDVinfection or a condition or symptom associated therewith, an infectionother than an influenza virus infection, NDV infection or a condition orsymptom associated therewith).

As used herein, the terms “treat,” “treatment,” and “treating” in thecontext of administration of a therapy to a subject for a disease refersto the eradication, reduction or amelioration of symptoms of saiddisease. With respect to infections (e.g., influenza virus, or NDVvirus), treatment refers to the eradication or control of thereplication of an infectious agent (e.g., a virus), the reduction in thenumbers of an infectious agent (e.g., the reduction in the titer ofvirus), the reduction or amelioration of the progression, severity,and/or duration of an infection (e.g., an influenza infection, NDVinfection or a condition or symptoms associated therewith, an infectionother than an influenza virus infection, NDV infection or a condition orsymptom associated therewith), or the amelioration of one or moresymptoms resulting from the administration of one or more therapies(including, but not limited to, the administration of one or moreprophylactic or therapeutic agents). With respect to cancer, treatmentrefers to the eradication, removal, modification, or control of primary,regional, or metastatic cancer tissue that results from theadministration of one or more therapeutic agents of the invention. Incertain embodiments, such terms refer to the minimizing or delaying thespread of cancer resulting from the administration of one or moretherapeutic agents of the invention to a subject with such a disease. Inother embodiments, such terms refer to elimination of disease causingcells.

4. DESCRIPTION OF THE FIGURES

FIG. 1. Schematic representation of a hybrid NAf-HN construct

The construct encodes nucleotides of the 3′ noncoding region of the WSNNA vRNA, the NA coding region corresponding to the cytoplasmic tail andtransmembrane domains of the NA protein plus the first amino acid of theNA ectodomain, the coding region of the NDV B1 HN protein (ectodomainonly), two sequential stop codons, the untranslated nucleotides of theWSN NA reading frame and the 5′ noncoding region of the WSN vRNA.

FIG. 2. Schematic representation of alteration in polybasic amino acidsequence of HA

The nucleotide sequence identified as H5N1 HA represents nucleotides1013-1045 (SEQ ID NO:13; amino acid sequence SEQ ID NO:14) of the openreading frame of the HA surface glycoprotein of InfluenzaA/Vietnam/1203/04 (H5N1). Nucleotides 1026-1038 were replaced by thesingle nucleotide cytosine using excise PCR and site directedmutagenesis resulting in the nucleotide sequence of avirulent HA (SEQ IDNO:15; amino acid sequence SEQ ID NO:16). The sequence changecorresponds to the replacement of the polybasic sequence of 5 aminoacids with the single amino acid threonine.

FIG. 3. Schematic representation of alteration in nucleic acid sequenceof HA

The sequence identified as Avirulent HA represents nucleotides 1013-1033of the open reading frame of an HA surface glycoprotein based onconsensus sequences of the HA proteins of avirulent InfluenzaA/Vietnam/1203/04 (H5N1) (SEQ ID NO:15; amino acid sequence SEQ IDNO:16). Underlined adenosine residues were replaced such that mutationswere synonymous resulting in the nucleotide sequence SEQ ID NO:17 andamino acid sequence SEQ ID NO:16.

FIG. 4A, FIG. 4B, FIG. 4C, and FIG. 4D. Schematic of pPol1VN1203 NStruncation mutants

FIG. 4A. The coding region of NS gene segment of H5N1 is 833nucleotides. FIG. 4B. The pPol1VN1203 NS1-126 construct has a deletionin the NS gene from nucleotides 379-456 of the coding region, theinsertion of 3 stop codons and a BglII restriction site. FIG. 4C. ThepPol1VN1203 NS1-99 construct has a deletion in the NS gene fromnucleotides 298-456 of the coding region, the insertion of 4 stopcodons, a BglII restriction site and a PacI restriction site. FIG. 4D.The pPol1VN1203 NS1-73 construct has a deletion in the NS gene fromnucleotides 219-456 of the coding region, the insertion of 4 stopcodons, a Bg111 restriction site and a PacI restriction site.

FIG. 5. Schematic of pNDV/B1

The sequence depicted are flanked at the 3′ end by a T7 promoter and atthe 5′ end by a HDV ribozyme and T7 terminator. The insertion sitebetween the P an M genes comprises a unique XbaI restriction site.

FIG. 6. Western Blot Analysis of KGFR Expression in Chimeric rNDVViruses

The chimeric viruses rNDV (lane 1), rNDV-KGFR (lane 2) andrNDV-KGFR/F-CT (lane 3) were grown in 10-day old embryonated chickeneggs. Purified viruses subjected to Western blot analysis using a murineanti-KGFR and an anti-mouse HRPO as the primary and secondaryantibodies, respectively.

FIG. 7. Western Blot Analysis of 117 HA Expression in Chimeric rNDVViruses

The chimeric viruses rNDV (lane 1), rNDV-KGFR (lane 2) andrNDV-KGFR/F-CT (lane 3) were grown in 10-day old embryonated chickeneggs. Purified viruses subjected to Western blot analysis using a murineanti-KGFR and an anti-mouse HRPO as the primary and secondaryantibodies, respectively.

FIG. 8A and FIG. 8B. Modification of the Cleavage Site of the F Proteinof rNDV

FIG. 8A: Schematic representation of the rNDV/B1 genome with two orthree amino acid changes in the cleavage site of their F proteins(corresponding to amino acids 112-117; native rNDV/B1 cleavage site,GRQGR/L; rNDV/F2aa, RRQRR/L; and rNDV/F3aa, RRQRR/F). The peptide bondthat is cleaved in the F protein is indicated with a slash. FIG. 8B:Syncytia formation in CEF cells infected by rNDVs with modified Fproteins. CEF cells infected a multiplicity of infection of 0.001, withrNDV/B1, rNDV/F2aa, and rNDV/F3aa viruses. Viral spread was monitoredevery 24 hours by immunofluorescence assay.

FIG. 9A, FIG. 9B, FIG. 9C, and FIG. 9D. Construction andCharacterization of the Fusogenic rNDV vector Expressing HPAI H7 HAprotein.

FIG. 9A: Schematic representation of rNDV/F3aa chimeric H7 cDNAconstruct, with the GE/GS, Kozak, and partial H7 HA sequences presented(SEQ ID NO:36). FIG. 9B: Comparison of viral growth kinetics, Log TCIDvs Time after Inoculation (hrs). Square, rNDV/B1; triangle, rNDV/F3aa;bold asterisk, rNDV/B1-H7; asterisk, rNDV/F3aa-chimericH7. FIG. 9C:Expression of the WT H7 HA protein or the chimeric H7 HA protein incells infected with rNDVs. Lane 1, mock infected; lane 2, rNDV/F3aa;lane 3, rNDV/B1-H7; lane 4, rNDV/F3aa-chimericH7. Row 1 α-avian H7; row2, α-NDV. FIG. 9D: Incorporation of the chimeric H7 HA protein in rNDVvirions was increased as compared to that of WT H7 HA protein. Lane 1,rNDV/B1-H7; rNDV/F3aa-chimericH7. Row 1 α-avian H7; row 2, α-NDV.

5. DETAILED DESCRIPTION OF THE INVENTION

The present invention provides chimeric negative strand RNA virusesengineered to express fusion proteins that incorporate into the virion,methods for producing such chimeric viruses and the use of such viruses,for example as immunogens, in immunogenic formulations, or in in vitroassays. The chimeric viruses of the invention are characterized bydisplaying, on the surface of the virion, not only antigens associatedwith the virus but also the fusion protein.

The viruses that may be engineered in accordance with the methods of theinvention can be any enveloped virus. In a specific embodiment, theviruses that may be engineered in accordance with the methods of theinvention have segmented or non-segmented genomes, single stranded ordouble stranded genomes, and express at least one essential glycoprotein(e.g., NA, HA, HN or F) that is incorporated into the virial envelope.The viruses for use in accordance with the methods of the invention canbe selected from naturally occurring strains, variants or mutants;mutagenized viruses (e.g., by exposure to UV irradiation, mutagens,and/or passaging); reassortants (for viruses with segmented genomes);and/or genetically engineered viruses. For example, the mutant virusescan be generated by natural variation, exposure to UV irradiation,exposure to chemical mutagens, by passaging in non-permissive hosts, byreassortment (i.e., by coinfection of an attenuated segmented virus withanother strain having the desired antigens), and/or by geneticengineering (e.g., using “reverse genetics”). Non-limiting examples ofviruses with segmented genomes for use in accordance with the methods ofthe invention include viruses from the family orthomyxoviridae (e.g.,influenza viruses), bunyaviridae (e.g., Bunyamwera), reoviridae andarenaviridae (e.g., Lassa fever). Non-limiting examples of viruses withnon-segmented genomes for use in accordance with the methods of theinvention include coronaviridae (e.g., human corona virus (SARS)),hepadnaviridae (e.g. hepatitus A, B or C virus), herpesviridae (e.g.herpes simplex virus), poxviridae (e.g., smallpox), rhabdoviridae (e.g.,vesicular stomatitis virus (VSV), Sendai virus and rabies),paramyxoviridae (e.g., measles and respiratory syncytial virus), andfiloviridae (Marburg and Ebola viruses). In certain embodiments, thesegemented virus is influenza virus. In other embodiments thenon-segmented virus is NDV.

In certain embodiments, the viruses selected for use in the inventionare attenuated and/or have defective IFN antagonist activity; i.e., theyare infectious and can replicate in vivo, but only generate low titersresulting in subclinical levels of infection that are non-pathogenic.The viruses may be attenuated by any method known in the art and/orexemplified herein, e.g., engineering the virus to comprise a mutationin the NS1 gene or to comprise a modification in the polybasic aminoacid sequence before the cleavage site in the HA protein. Suchattenuated viruses engineered in accordance with the invention are thusideal candidates for immunogenic formulations, e.g., live virusvaccines. When administered to a subject, the attenuated, chimericviruses of the invention are capable of generating an immune responseand eliciting immunity to both the virus and to the non-native or fusionprotein. In some embodiments, the non-native protein is derived from apathogen. By extension, administration of such a chimeric virus to asubject generates an immune response and/or immunity to said pathogen inaddition to the virus.

The invention also relates to the use of the chimeric virus of theinvention in compositions (e.g. immunogenic formulations) for humans oranimals (e.g., avians). In particular, the chimeric viruses that areattenuated can be used as vaccines against a broad range of virus and/ordiseases. Because the chimeric virus is engineered to expressheterologous gene sequences as foreign epitopes in the virion,compositions comprising a chimeric virus of the invention (e.g., vaccineformulations) can be designed for immunization against multiple strainvariants, different viruses or against completely different infectiousagents or disease antigens (e.g., bacteria, parasites, fungi or tumorspecific antigens) from which the heterologous gene sequences arederived. Many methods may be used to introduce the live attenuated virusformulations to a human or animal subject to induce an immune orappropriate cytokine response. These include, but are not limited to,intranasal, intratrachial, oral, intradermal, intramuscular,intraperitoneal, intravenous and subcutaneous routes.

5.1 Chimeric Influenza Viruses

5.1.1 Chimeric Avian Influenza Virus Comprising a Fusion ProteinIncorporated in its Virion

The present invention encompasses the engineering of an avian influenzavirus such that a fusion protein is encoded by the genome and, whenexpressed, is incorporated into the virion. Any avian influenza virustype, subtype or strain that can be engineered to express andincorporate the fusion protein into the avian influenza virion can beselected and used in accordance with the invention including, but notlimited to, naturally occurring strains, variants or mutants,mutagenized viruses, reassortants and/or genetically engineered viruses.In a specific embodiment, the avian influenza viruses of the inventionare not naturally occurring viruses. In another specific embodiment, theavian influenza viruses of the invention are genetically engineeredviruses. Non-limiting examples of avian influenza viruses includeInfluenza A subtype H5N1, H6N2, H7N3, H9N2 and H10N7.

Genetic manipulation of the influenza virus requires engineering atleast one of the eight viral RNA segments which comprise the viralgenome. Mutagenesis of the genome may be achieved through “reverseengineering” techniques (see section 5.4). The plasticity of theinfluenza genome is, however, limited both in the number of segments andin the length of segments that may be stably integrated into the virus.The overall stability of long inserts is unknown and the segmentscomprising such inserts, or portions thereof, may be lost due to viralassortment after a few generations. Thus, in a preferred embodiment ofthe invention, the avian influenza virus is engineered such that one ofits two major surface proteins is replaced by a fusion protein.

Accordingly, the present invention provides a chimeric avian influenzavirus, comprising at least one fusion protein comprising an ectodomain(ED) of a protein of infectious agent other than an influenza virus andthe cytoplasmic (CT) and transmembrane (TM) domains or the transmembrane(TM) domain of at least one essential influenza virus glycoprotein,wherein the at least one fusion protein functionally replaces at leastone essential avian influenza virus glycoprotein. In other words, theavian influenza virus serves as the “backbone” that is engineered toexpress and incorporate into its virion the fusion protein in place ofan essential avian influenza virus glycoprotein. The inclusion of the TMand CT domains or TM domain of an influenza virus glycoproteincorresponding to the essential avian influenza virus glycoproteinfunctionally replaced by the fusion protein permits the fusion proteinto incorporate into the virion of the avian influenza virus. The TM andCT domains or TM domain of the fusion protein may correspond to or bederived from any influenza virus that permits the fusion protein toincorporate into the virion of the avian influenza virus backbone.

In certain embodiments, the TM and CT domains or the TM domain of thefusion protein correspond to the TM and CT domains or the TM domain of adifferent type, subtype or strain of avian influenza virus than thebackbone avian influenza virus. In other embodiments, the TM and CTdomains or the TM domain of the fusion protein correspond to the TM andCT domains or the TM domain of an influenza virus other than an avianinfluenza virus. In other embodiments, the TM and CT domains or the TMdomain of the fusion protein correspond to the TM and CT domains or theTM domain of the avian influenza virus backbone.

The avian influenza virion comprises two major surface glycoproteins,hemagglutinin (HA) and neuraminidase (N), both of which comprise acytoplasmic domain, a transmembrane domain and an ectodomain.Accordingly, in certain embodiments, the TM and CT domains of the fusionprotein correspond to the TM and CT domains of either an HA protein oran NA protein of an influenza virus. Since the CT domain of HA or NA maynot be necessary for incorporation of the fusion protein into the avianinfluenza virus virion, the fusion protein, in some embodiments, isengineered to contain only the TM domain of HA or NA. For example, theCT domain of NA has been shown to be unnecessary for the properpackaging of this protein into influenza A viral envelopes(Garcia-Sastre et al., 1995, Virus Res. 37:37-47, which is herebyincorporated by reference in its entirety). Therefore, where structuraldomains corresponding to those of an NA protein are used in the creationof the fusion protein, the invention encompasses engineering the fusionprotein to contain only a TM domain corresponding to an influenza virusNA protein. Accordingly, in one embodiment of the invention, the fusionprotein is engineered to contain only a TM domain, which TM domaincorresponds to the TM domain of an influenza virus NA protein.

The TM and CT domains of influenza virus HA and NA proteins arestructurally distinct in that the domains are located at the C-terminusof the HA protein and the N-terminus of the NA protein. Apart from thediffering orientation of the two domains in each class of surfaceglycoprotein, the HA and CT structural domains may comprise yet unknowndifferences in functionality dependent on their relative placementwithin a polypeptide chain. Therefore, when designing the fusion proteinto be engineered into the avian influenza virus, the orientation of theectodomain of the infectious agent to be fused to the TM and CT domainsor the TM domain of an influenza virus glycoprotein will guide theselection of the TM and CT domains or the TM domain. For example, wherethe ectodomain of an infectious agent is anchored by the N-terminus, theTM and CT domains of an influenza virus NA protein may used.

HA and NA exhibit competing activities with respect to cellular fusionand release, respectively, that are necessary for the infectivity andpropagation of the virus. HA binds to N-AcetylNeuraminic Acid (NeuNAc;sialic acid) on a cell surface leading to uptake of the virus by a hostcell, while NA cleaves sialic acid moieties from the cell surfaceleading to release of progeny virus from an infected cell. Disruption ofeither of these activities results in a non-functional virus.Accordingly, to maintain viral competence, where a surface glycoproteinis replaced, its function in the chimeric virus must be supplied by thefusion protein. In one embodiment of the invention, the chimeric avianinfluenza virus comprises a fusion protein that exhibits neuraminidaseactivity. In another embodiment of the invention, the chimeric avianinfluenza virus comprises a fusion protein that exhibits receptorbinding activity. In yet another embodiment of the invention, thechimeric avian influenza virus comprises two fusion proteins one ofwhich exhibits neuraminidase activity, the other of which exhibitsreceptor binding activity. In still other embodiments, the chimericavian influenza virus comprises a fusion protein comprising an epitopeof a heterologous infectious agent, which fusion protein exhibitsexhibits neuraminidase activity or receptor binding activity. In anotherembodiment of the invention, the chimeric avian influenza viruscomprises a fusion protein that exhibits receptor binding activity. In aspecific embodiment, the chimeric avian influenza virus comprises asurface protein containing the ectodomain of the HN protein of NewcastleDisease Virus (NDV) and the TM and CT domains of the NA protein ofInfluenza A/WSN/33, which HN ectodomain exhibits neuraminidase activity.In other embodiments, the chimeric avian influenza virus comprises asurface protein containing the ectodomain of the HA protein of aheterologous influenza virus (e.g., the H7 HA protein or H9 HA protein).HA and NA are encoded by separate segments of the viral genome andreplacement of the entire coding region of the native protein eliminatesmost length constraints on the sequence encoding the introduced protein.

In certain embodiments, the fusion protein comprises the transmembranedomain plus 1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1 immediatelyadjacent residue(s) of the ectodomain of an essential influenza virusglycoprotein. For example, in a specific embodiment, the fusion proteincomprises the transmembrane domain of an influenza virus NA protein, 1to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1 immediately adjacent residue(s)of the ectodomain of the influenza virus NA protein, and the ectodomain,or fragment thereof, of an infectious agent other than influenza virussuch that the fusion protein can functionally replace the function of NAprotein. In another specific embodiment, the fusion protein comprisesthe cytoplasmic and transmembrane domains of an influenza virus NAprotein, 1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1 residue(s) of theectodomain of the influenza virus NA protein that are immediatelyadjacent to the transmembrane domain of the influenza virus NA protein,and the ectodomain, or fragment thereof, of an infectious agent otherthan influenza virus such that the fusion protein can functionallyreplace the NA protein. In another embodiment, the fusion proteincomprises the transmembrane domain or cytoplasmic and transmembranedomains of an NA protein, the complete stalk domain, or a fragmentthereof, of an NA protein that precedes its globular head, and theectodomain, or fragment thereof, of an infectious agent other thaninfluenza virus such that the fusion protein can functionally replacethe function of NA protein. In another specific embodiment, the fusionprotein comprises the transmembrane domain of an influenza virus HAprotein, 1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1 immediately adjacentresidue(s) of the ectodomain of the influenza virus HA protein, and theectodomain, or fragment thereof, of an infectious agent other thaninfluenza virus such that the fusion protein can functionally replacethe function of HA protein. In another specific embodiment, the fusionprotein comprises the cytoplasmic and transmembrane domains of aninfluenza virus HA protein, 1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1residue(s) of the ectodomain of the influenza virus HA protein that areimmediately adjacent to the transmembrane domain of the influenza virusHA protein, and the ectodomain, or fragment thereof, of an infectiousagent other than influenza virus such that the fusion protein canfunctionally replace the HA protein.

In certain embodiments, the at least one fusion protein of the chimericavian influenza virus of the invention does not comprise the completeectodomain of a heterologous protein (e.g., comprises an antigenicfragment of the ectodomain of a protein of a heterologous infectiousagent), and may or may not further comprise one or more fragments of theectodomain of a native essential glycoprotein. Accordingly, in certainembodiments, the ectodomain of the fusion protein may comprise afragment of the ectodomain of a protein of a heterologous infectiousagent. In other embodiments, the ectodomain of the fusion protein maycomprise fragments of both a native essential glycoprotein and a proteinof a heterologous infectious agent. In embodiments where the fusionprotein replaces an essential surface glycoprotein, the function of thesurface glycoprotein must be supplied by the fusion protein, i.e., thefusion protein must exhibit the functionality of the surfaceglycoprotein that it is replacing.

The present invention encompasses nucleotide sequences (i.e.,recombinant segments) encoding the fusion proteins described in thisSection 5.1.1. In preferred embodiments, the recombinant segmentscomprising nucleic acids encoding the fusion proteins described inSection 5.1.1 comprise 3′ and 5′ incorporation signals which arerequired for proper replication, transcription and packaging of thevRNAs (Fujii et al., 2003, Proc. Natl. Acad. Sci. USA 100:2002-2007;Zheng, et al., 1996, Virology 217:242-251, both of which areincorporated by reference herein in their entireties). In a preferredembodiment, the recombinant segments of the invention therefore use the3′ and 5′ noncoding and/or nontranslated sequences of segments ofviruses within the same viral type or strain as the backbone avianinfluenza virus. In specific embodiments, the recombinant segmentscomprise nucleic acids encoding the fusion proteins described in thisSection, 5.1.1, which comprise the 3′ noncoding region of an influenzavirus NA vRNA, the NA coding region corresponding to the CT and TMdomains of the NA protein, 1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1residue(s) of the ectodomain of the influenza virus NA protein that areimmediately adjacent to the transmembrane domain of the influenza virusNA protein, the untranslated regions of the NA protein reading frame andthe 5′non-coding region of the NA vRNA.

As an alternative to replacing the NA or HA proteins of avian influenzavirus, “reverse genetic” and bicistronic techniques may be used toproduce a chimeric influenza virus comprising an ectodomain, or afragment thereof, of a protein of an infectious agent other thaninfluenza virus and the TM and/or CT domains of an influenza virus. See,e.g., U.S. Pat. No. 6,887,699, U.S. Pat. No. 6,001,634, U.S. Pat. No.5,854,037 and U.S. Pat. No. 5,820,871, each of which is herebyincorporated by reference in its entirety. The bicistronic approachesinvolve inserting the coding region of the fusion protein into the openreading frame of a necessary protein of the virus and its stop codon.The insertion is flanked by an IRES and any untranslated signalsequences of the necessary protein in which it is inserted and must notdisrupt the open reading frame, packaging signal, polyadenylation ortranscriptional promoters of the necessary viral protein. Any IRES wellknown in the art or described herein may be used in accordance with theinvention (e.g., the IRES of BiP gene, nucleotides 372 to 592 of GenBankdatabase entry HUMGRP78; or the IRES of encephalomyocarditis virus(EMCV), nucleotides 1430-2115 of GenBank database entry CQ867238.).Since the function of HA or NA is not being replaced when thebicistronic approach is used, the ectodomain portion of the fusionprotein is not limited to a protein that provides the function of thereplaced HA or NA protein. The ectodomain of such a fusion protein maycorrespond to any heterologous molecule, or comprise a fragment of anyheterologous molecule, including but not limited to antigens, diseaseantigens and antigens derived from any protein of an infectious agent(e.g. any protective antigen associated with viral, bacterial orparasitic infectious agents). Non-limiting examples of antigens derivedfrom or associated with infectious agents for use in accordance with themethods of the invention are provided in Section 5.3, infra.

Replacement of a necessary surface protein of the backbone virus orintroduction of a recombinant segment into the viral genome mayattenuate the resulting chimeric virus, i.e., the chimeric virus willexhibit impaired replication relative to wild type. In certainembodiments of the invention, attenuation of the chimeric virus isdesired such that the chimeric virus remains, at least partially,infectious and can replicate in vivo, but only generate low titersresulting in subclinical levels of infection that are non-pathogenic.Such attenuated chimeric viruses are especially suited for embodimentsof the invention wherein the virus is administered to a subject in orderto act as an immunogen, e.g., a live vaccine. The viruses may beattenuated by any method known in the art and/or exemplified herein,e.g., engineering the virus to comprise a mutation in the NS1 gene or tocomprise a modification in the polybasic amino acid sequence before thecleavage site in the HA protein (see U.S. Pat. No. 6,468,544; U.S. Pat.No. 6,669,943; Li et al., 1999, J. Infect. Dis. 179:1132-1138, each ofwhich is hereby incorporated by reference in its entirety).

In one embodiment, an attenuated chimeric avian influenza virus of theinvention comprises a genome comprising a mutation in the NS1 gene ofthe avian influenza backbone virus, which is known in other influenzaviruses to diminish the ability of the NS1 gene product to antagonize acellular interferon response. In another embodiment, an attenuatedchimeric avian influenza virus of the invention comprises a genomecomprising a mutation in the HA gene of the avian influenza backbonevirus, which is known in other influenza viruses to diminish oreliminate the ability of cellular proteases to cleave the protein intoits active form and thereby reduce or eliminate HA induced fusion andinfectivity. In yet another embodiment, an attenuated chimeric avianinfluenza virus of the invention comprises a genome comprising amutation in both the HA gene and NS1 gene of the avian influenzabackbone virus, which are known in other influenza viruses to eitherseparately or when combined to reduce or diminish viral activity. Thetiters of attenuated-chimeric and wild-type avian influenza viruses canbe determined utilizing any technique well-known in the art or describedherein, (e.g., hemagglutination assays, plaque assays, egg infectiousdoses (EID50), tissue culture infectious doses (TCID50), etc.) and theviruses can be propagated under conditions described herein orwell-known in the art (e.g., in CEF cells, MDCK cells (e.g., in MEM, 10%v/v fetal calf serum (FCS), 1% penicillin/streptomycin at 37° C. in a 5%CO₂ humidified incubator) or embryonated chicken eggs (e.g., in astationary incubator at 37° C. with 55% relative humidity).Alternatively, the viruses can be propagated in cells (e.g., CEF cells,MDCK cells, etc.) that are grown in serum-free or serum reduced (e.g.,TPCK trypsin) medium.

5.1.2 Chimeric Attenuated Influenza Virus Comprising a Fusion ProteinIncorporated in its Virion

The present invention encompasses the engineering of an attenuatedinfluenza virus such that a fusion protein is encoded by the genome and,when expressed, is incorporated into the virion. In other words, theinvention encompasses the use of an attenuated influenza virus (theparental virus) as the “backbone” that is engineered to express andincorporate into its virion the fusion protein. Any attenuated influenzavirus type or strain including, but not limited to, naturally occurringstrains, variants or mutants, mutagenized viruses, reassortants and/orgenetically modified viruses may be used as the backbone of that isengineered to express and incorporate into its virion the fusionprotein. In a specific embodiment, the parental influenza viruses foruse in accordance with the invention are not naturally occurringviruses. In another specific embodiment, the parental influenza virusesfor use in accordance with the invention are genetically engineeredviruses.

Influenza viruses for use as the backbone virus in accordance with theinvention may naturally have an attenuated phenotype or may beengineered to comprise a mutation associated with an attenuatedphenotype, where such mutation is known in the art or described herein(e.g. a mutation in the viral NS1 protein or viral HA protein). Inspecific embodiments, the attenuated virus is influenza A. In otherembodiments, the attenuated virus is influenza B. In yet otherembodiments, the attenuated virus is influenza C. Nonlimiting examplesof influenza viruses which may be engineered in accordance with theinvention include Influenza A subtype H10N4, subtype H10N5, subtypeH10N7, subtype H10N8, subtype H10N9, subtype H11N1, subtype H11N13,subtype H11N2, subtype H11N4, subtype H11N6, subtype H11N8, subtypeH11N9, subtype H12N1, subtype H12N4, subtype H12N5, subtype H12N8,subtype H13N2, subtype H13N3, subtype H13N6, subtype H13N7, subtypeH14N5, subtype H14N6, subtype H15N8, subtype H15N9, subtype H16N3,subtype H1N1, subtype H1N2, subtype H1N3, subtype H1N6, subtype H1N9,subtype H2N1, subtype H2N2, subtype H2N3, subtype H2N5, subtype H2N7,subtype H2N8, subtype H2N9, subtype H3N1, subtype H3N2, subtype H3N3,subtype H3N4, subtype H3N5, subtype H3N6, subtype H3N8, subtype H3N9,subtype H4N1, subtype H4N2, subtype H4N3, subtype H4N4, subtype H4N5,subtype H4N6, subtype H4N8, subtype H4N9, subtype H5N1, subtype H5N2,subtype H5N3, subtype H5N4, subtype H5N6, subtype H5N7, subtype H5N8,subtype H5N9, subtype H6N1, subtype H6N2, subtype H6N3, subtype H6N4,subtype H6N5, subtype H6N6, subtype H6N7, subtype H6N8, subtype H6N9,subtype H7N1, subtype H7N2, subtype H7N3, subtype H7N4, subtype H7N5,subtype H7N7, subtype H7N8, subtype H7N9, subtype H8N4, subtype H8N5,subtype H9N1, subtype H9N2, subtype H9N3, subtype H9N5, subtype H9N6,subtype H9N7, subtype H9N8, or subtype H9N9; Influenza B strainAichi/5/88, strain Akita/27/2001, strain Akita/5/2001, strainAlaska/16/2000, strain Alaska/1777/2005, strain Argentina/69/2001,strain Arizona/146/2005, strain Arizona/148/2005, strain Bangkok/163/90,strain Bangkok/34/99, strain Bangkok/460/03, strain Bangkok/54/99,strain Barcelona/215/03, strain Beijing/15/84, strain Beijing/184/93,strain Beijing/243/97, strain Beijing/43/75, strain Beijing/5/76, strainBeijing/76/98, strain Belgium/WV106/2002, strain Belgium/WV107/2002,strain Belgium/WV109/2002, strain Belgium/WV114/2002, strainBelgium/WV122/2002, strain Bonn/43, strain Brazil/952/2001, strainBucharest/795/03, strain Buenos Aires/161/00), strain Buenos Aires/9/95,strain Buenos Aires/SW16/97, strain Buenos Aires/VL518/99, strainCanada/464/2001, strain Canada/464/2002, strain Chaco/366/00, strainChaco/R113/00, strain Cheju/303/03, strain Chiba/447/98, strainChongqing/3/2000, strain clinical isolate SA1 Thailand/2002, strainclinical isolate SA10 Thailand/2002, strain clinical isolate SA100Philippines/2002, strain clinical isolate SA101 Philippines/2002, strainclinical isolate SA110 Philippines/2002), strain clinical isolate SA112Philippines/2002, strain clinical isolate SA113 Philippines/2002, strainclinical isolate SA114 Philippines/2002, strain clinical isolate SA2Thailand/2002, strain clinical isolate SA20 Thailand/2002, strainclinical isolate SA38 Philippines/2002, strain clinical isolate SA39Thailand/2002, strain clinical isolate SA99 Philippines/2002, strainCNIC/27/2001, strain Colorado/2597/2004, strain Cordoba/VA418/99, strainCzechoslovakia/16/89, strain Czechoslovakia/69/90, strain Daeku/10/97,strain Daeku/45/97, strain Daeku/47/97, strain Daeku/9/97, strainB/Du/4/78, strain B/Durban/39/98, strain Durban/43/98, strainDurban/44/98, strain B/Durban/52/98, strain Durban/55/98, strainDurban/56/98, strain England/1716/2005, strain England/2054/2005),strain England/23/04, strain Finland/154/2002, strain Finland/159/2002,strain Finland/160/2002, strain Finland/161/2002, strain Finland/162/03,strain Finland/162/2002, strain Finland/162/91, strain Finland/164/2003,strain Finland/172/91, strain Finland/173/2003, strain Finland/176/2003,strain Finland/184/91, strain Finland/188/2003, strain Finland/190/2003,strain Finland/220/2003, strain Finland/WV5/2002, strain Fujian/36/82,strain Geneva/5079/03, strain Genoa/11/02, strain Genoa/2/02, strainGenoa/21/02, strain Genova/54/02, strain Genova/55/02, strainGuangdong/05/94, strain Guangdong/08/93, strain Guangdong/5/94, strainGuangdong/55/89, strain Guangdong/8/93, strain Guangzhou/7/97, strainGuangzhou/86/92, strain Guangzhou/87/92, strain Gyeonggi/592/2005,strain Hannover/2/90, strain Harbin/07/94, strain Hawaii/10/2001, strainHawaii/1990/2004, strain Hawaii/38/2001, strain Hawaii/9/2001, strainHebei/19/94, strain Hebei/3/94), strain Henan/22/97, strainHiroshima/23/2001, strain Hong Kong/110/99, strain Hong Kong/1115/2002,strain Hong Kong/112/2001, strain Hong Kong/123/2001, strain HongKong/1351/2002, strain Hong Kong/1434/2002, strain Hong Kong/147/99,strain Hong Kong/156/99, strain Hong Kong/157/99, strain HongKong/22/2001, strain Hong Kong/22/89, strain Hong Kong/336/2001, strainHong Kong/666/2001, strain Hong Kong/9/89, strain Houston/1/91, strainHouston/1/96, strain Houston/2/96, strain Hunan/4/72, strainIbaraki/2/85, strain ncheon/297/2005, strain India/3/89, strainIndia/77276/2001, strain Israel/95/03, strain Israel/WV187/2002, strainJapan/1224/2005, strain Jiangsu/10/03, strain Johannesburg/1/99, strainJohannesburg/96/01, strain Kadoma/1076/99, strain Kadoma/122/99, strainKagoshima/15/94, strain Kansas/22992/99, strain Khazkov/224/91, strainKobe/1/2002, strain, strain Kouchi/193/99, strain Lazio/1/02, strainLee/40, strain Leningrad/129/91, strain Lissabon/2/90), strain LosAngeles/1/02, strain Lusaka/270/99, strain Lyon/1271/96, strainMalaysia/83077/2001, strain Maputo/1/99, strain Mar del Plata/595/99,strain Maryland/1/01, strain Memphis/1/01, strain Memphis/12/97-MA,strain Michigan/22572/99, strain Mie/1/93, strain Milano/1/01, strainMinsk/318/90, strain Moscow/3/03, strain Nagoya/20/99, strainNanchang/1/00, strain Nashville/107/93, strain Nashville/45/91, strainNebraska/2/01, strain Netherland/801/90, strain Netherlands/429/98,strain New York/1/2002, strain NIB/48/90, strain Ningxia/45/83, strainNorway/1/84, strain Oman/16299/2001, strain Osaka/1059/97, strainOsaka/983/97-V2, strain Oslo/1329/2002, strain Oslo/1846/2002, strainPanama/45/90, strain Paris/329/90, strain Parma/23/02, strainPerth/211/2001, strain Peru/1364/2004, strain Philippines/5072/2001,strain Pusan/270/99, strain Quebec/173/98, strain Quebec/465/98, strainQuebec/7/01, strain Roma/1/03, strain Saga/S172/99, strain Seoul/13/95,strain Seoul/37/91, strain Shangdong/7/97, strain Shanghai/361/2002),strain Shiga/T30/98, strain Sichuan/379/99, strain Singapore/222/79,strain Spain/WV27/2002, strain Stockholm/10/90, strainSwitzerland/5441/90, strain Taiwan/0409/00, strain Taiwan/0722/02,strain Taiwan/97271/2001, strain Tehran/80/02, strain Tokyo/6/98, strainTrieste/28/02, strain Ulan Ude/4/02, strain United Kingdom/34304/99,strain USSR/100/83, strain Victoria/103/89, strain Vienna/1/99, strainWuhan/356/2000, strain WV194/2002, strain Xuanwu/23/82, strainYamagata/1311/2003, strain Yamagata/K500/2001, strain Alaska/12/96,strain GA/86, strain NAGASAKI/1/87, strain Tokyo/942/96, or strainRochester/02/2001; Influenza C strain Aichi/1/81, strain Ann Arbor/1/50,strain Aomori/74, strain California/78, strain England/83, strainGreece/79, strain Hiroshima/246/2000, strain Hiroshima/252/2000, strainHyogo/1/83, strain Johannesburg/66, strain Kanagawa/1/76, strainKyoto/1/79, strain Mississippi/80, strain Miyagi/1/97, strainMiyagi/5/2000, strain Miyagi/9/96, strain Nara/2/85, strainNewJersey/76, strain pig/Beijing/115/81, strain Saitama/3/2000), strainShizuoka/79, strain Yamagata/2/98, strain Yamagata/6/2000, strainYamagata/9/96, strain BERLIN/1/85, strain ENGLAND/892/8, strain GREATLAKES/1167/54, strain JJ/50, strain PIG/BEIJING/10/81, strainPIG/BEIJING/439/82), strain TAYLOR/1233/47, or strain STRAINC/YAMAGATA/10/81.

In one embodiment, the attenuated influenza virus (the parental virus)used in accordance with the invention has an impaired ability toantagonize the cellular interferon (IFN). In a specific embodiment, theattenuated influenza virus (the parental virus) used in accordance withthe invention is an influenza virus type or strain comprising a mutationin the NS1 gene that results in an impaired ability of the virus toantagonize the cellular interferon response. Examples of the types ofmutations that can be introduced into the influenza virus NS1 geneinclude deletions, substitutions, insertions and combinations thereof.One or more mutations can be introduced anywhere throughout the NS1 gene(e.g., the N-terminus, the C-terminus or somewhere in between) and/orthe regulatory element of the NS1 gene. In a specific embodiment, anattenuated influenza virus (the parental virus) used in accordance withthe invention comprises a genome having an influenza virus NS1 gene witha mutation at the N-terminus. In another embodiment, an attenuatedinfluenza virus (the parental virus) comprises a genome having aninfluenza virus NS1 gene with a mutation at the C-terminus. In anotherembodiment, an attenuated influenza virus (the parental virus) used inaccordance with the invention comprises a genome having a mutation in aninfluenza virus NS1 gene resulting in a deletion consisting of 5,preferably 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 75, 80, 85,90, 95, 99, 100, 105, 110, 115, 120, 125, 126, 130, 135, 140, 145, 150,155, 160, 165, 170 or 175 amino acid residues from the C-terminus ofNS1, or a deletion of between 5-170, 25-170, 50-170, 100-170, 100-160,or 105-160 amino acid residues from the C-terminus. In anotherembodiment, an attenuated influenza virus (the parental virus) used inaccordance with the invention comprises a genome having a mutation in aninfluenza virus NS1 gene resulting in a deletion of all amino acidresidues except amino acid residues 1-126, amino acid residues 1-120,amino acid residues 1-115, amino acid residues 1-110, amino acidresidues 1-100, amino acid residues 1-99, amino acid residues 1-95,amino acid residues 1-85, amino acid residues 1-80, amino acid residues1-75, amino acid residues 1-73, amino acid residues 1-70, amino acidresidues 1-65 or amino acid residues 1-60, wherein the N-terminus aminoacid is number 1.

In one embodiment, an attenuated influenza virus of the inventioncomprises a genome comprising a mutation in the NS1 gene of theinfluenza virus backbone, which diminishes the ability of the NS1 geneproduct to antagonize a cellular interferon response, and permits theattenuated virus, at a multiplicity of infection (MOI) of between 0.0005and 0.001, 0.001 and 0.01, 0.01 and 0.1, or 0.1 and 1, or a MOI of0.0005, 0.0007, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1.0, 1.5, 2.0, 2.5,3.0, 3.5, 4.0, 4.5, 5.0, 5.5, or 6.0, to grow to titers betweenapproximately 1 to approximately 100 fold, approximately 5 toapproximately 80 fold, approximately 20 to approximately 80 fold, orapproximately 40 to approximately 80 fold, approximately 1 toapproximately 10 fold, approximately 1 to approximately 5 fold,approximately 1 to approximately 4 fold, approximately 1 toapproximately 3 fold, approximately 1 to approximately 2 fold, orapproximately 1, 2, 3, 4, 5, 6, 7, 8, 10, 15, 20, 25, 30, 35, 40, 45,50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100 fold lower than thewild-type influenza virus in cells (e.g., cells of human, mouse, rat,porcine, dog, horse, or avian origin (e.g., HEp-2, A549, 293T,Madin-Darby canine kidney cells (MDCK) or chicken embryo fibroblasts(CEF)), as determined approximately 2 to 10 days, 3 to 7 days, 3 to 5days, or 2, 3, 4, 5, 6, 7, 8, 9, 10 days post-infection when propagatedunder the same conditions. The titers of attenuated and wild-typeinfluenza viruses can be determined utilizing any technique well-knownin the art or described herein, (e.g., hemagglutination assays, plaqueassays, egg infectious doses (EID50), tissue culture infectious doses(TCID50), etc.) and the viruses can be propagated under conditionsdescribed herein or well-known in the art (e.g., in CEF cells, MDCKcells (e.g., in MEM, 10% v/v fetal calf serum (FCS), 1%penicillin/streptomycin at 37° C. in a 5% CO₂ humidified incubator) orembryonated chicken eggs (e.g., in a stationary incubator at 37° C. with55% relative humidity). Alternatively, the viruses can be propagated incells (e.g., CEF cells, MDCK cells, etc.) that are grown in serum-freeor serum reduced (e.g., TPCK trypsin) medium.

In another embodiment, the attenuated influenza virus (the parentalvirus) used in accordance with the invention comprises a genomecomprising a mutation in the HA gene of the influenza backbone virusthat diminishes or eliminates the ability of cellular proteases tocleave the protein into its active form. Examples of the types ofmutations that may be introduced into the influenza HA gene includedeletions, substitutions, insertions or combinations thereof. The one ormore mutations are preferably introduced at the HA cleavage site (e.g.,nucleotides 1013-1039 of GenBank entry AY818135). In general, mutationswhich decrease the cleavability of the HA protein as determined bystandard methods in CEF correlate with decreased virulence in in vivoassays (Horimoto and Kawaoka, 1994, 68:3120-3128; which is herebyincorporated by reference in its entirety). In a specific embodiment, anattenuated influenza virus (the parental virus) used in accordance withthe invention comprises a genome having a mutation in the influenzavirus HA gene resulting in the substitution of nucleotides 1026-1038with the single nucleotide thymine. In another embodiment, an attenuatedinfluenza virus of the invention comprises a genome comprising amutation in the HA gene of the influenza backbone virus that diminishesor eliminates the ability of cellular proteases to cleave the proteininto its active form, and permits the attenuated virus, at amultiplicity of infection (MOI) of between 0.0005 and 0.001, 0.001 and0.01, 0.01 and 0.1, or 0.1 and 1, or a MOI of 0.0005, 0.0007, 0.001,0.005, 0.01, 0.05, 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5,5.0, 5.5, or 6.0, to grow to titers between approximately 1 toapproximately 100 fold, approximately 5 to approximately 80 fold,approximately 20 to approximately 80 fold, or approximately 40 toapproximately 80 fold, approximately 1 to approximately 10 fold,approximately 1 to approximately 5 fold, approximately 1 toapproximately 4 fold, approximately 1 to approximately 3 fold,approximately 1 to approximately 2 fold, or approximately 1, 2, 3, 4, 5,6, 7, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85,90, 95 or 100 fold lower than the wild-type influenza virus in cells(e.g., cells of human, mouse, rat, porcine, dog, horse, or avian origin(e.g., HEp-2, A549, 293T, Madin-Darby canine kidney cells (MDCK) orchicken embryo fibroblasts (CEF)), as determined approximately 2 to 10days, 3 to 7 days, 3 to 5 days, or 2, 3, 4, 5, 6, 7, 8, 9, 10 dayspost-infection when propagated under the same conditions. The HA proteincomprising such a mutation is not antigenically distinct from thewild-type parental HA protein, i.e., all antibodies raised against thewild-type HA protein will cross react with the mutated HA protein andall antibodies raised against the mutated HA protein will cross reactwith the wild-type HA protein. The titers of attenuated and wild-typeinfluenza viruses can be determined utilizing any technique well-knownin the art or described herein, (e.g., hemagglutination assays, plaqueassays, egg infectious doses (EID50), tissue culture infectious doses(TCID50), etc.) and the viruses can be propagated under conditionsdescribed herein or well-known in the art (e.g., in CEF cells, MDCKcells (e.g., in MEM, 10% v/v fetal calf serum (FCS), 1%penicillin/streptomycin at 37° C. in a 5% CO₂ humidified incubator) orembryonated chicken eggs (e.g., in a stationary incubator at 37° C. with55% relative humidity). Alternatively, the viruses can be propagated incells (e.g., CEF cells, MDCK cells, etc.) that are grown in serum-freeor serum reduced (e.g., TPCK trypsin) medium.

In another embodiment, the attenuated influenza virus (the parentalvirus) used in accordance with the invention comprises a genomecomprising: (i) a mutation in the HA gene of the influenza backbonevirus that diminishes or eliminates the ability of cellular proteases tocleave the protein into its active form, and (ii) a mutation in the NS1gene that results in an impaired ability of the virus to antagonize thecellular interferon response. In another embodiment, an attenuatedinfluenza virus of the invention comprises a genome comprising amutation in both the HA gene and NS1 gene of the influenza backbonevirus that permits the attenuated virus, at a multiplicity of infection(MOI) of between 0.0005 and 0.001, 0.001 and 0.01, 0.01 and 0.1, or 0.1and 1, or a MOI of 0.0005, 0.0007, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5,1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, or 6.0, to grow totiters between approximately 1 to approximately 100 fold, approximately5 to approximately 80 fold, approximately 20 to approximately 80 fold,or approximately 40 to approximately 80 fold, approximately 1 toapproximately 10 fold, approximately 1 to approximately 5 fold,approximately 1 to approximately 4 fold, approximately 1 toapproximately 3 fold, approximately 1 to approximately 2 fold, orapproximately 1, 2, 3, 4, 5, 6, 7, 8, 10, 15, 20, 25, 30, 35, 40, 45,50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100 fold lower than thewild-type influenza virus in cells (e.g., cells of human, mouse, rat,porcine, dog, horse, or avian origin (e.g., HEp-2, A549, 293T,Madin-Darby canine kidney cells (MDCK) or chicken embryo fibroblasts(CEF)), as determined approximately 2 to 10 days, 3 to 7 days, 3 to 5days, or 2, 3, 4, 5, 6, 7, 8, 9, 10 days post-infection when propagatedunder the same conditions.

The present invention provides a chimeric attenuated influenza virus,comprising at least one fusion protein having an ectodomain (ED), orfragment thereof, of an infectious agent other than an influenza virusand the cytoplasmic (CT) and transmembrane (TM) domains or thetransmembrane domain of an essential influenza virus glycoprotein,wherein the at least one fusion protein functionally replaces at leastone essential influenza virus glycoprotein. In other words, theattenuated influenza virus serves as the “backbone” that is engineeredto express and incorporate into its virion the at least one fusionprotein in place of an essential influenza virus glycoprotein. Theinclusion of the TM and CT domains or TM domain of an influenza virusglycoprotein corresponding to the essential influenza virus glycoproteinfunctionally replaced by the fusion protein permits the fusion proteinto incorporate into the virion of the attenuated influenza virus. The TMand CT domains or TM domain of the fusion protein may correspond to orbe derived from any influenza virus that permits the fusion protein toincorporate into the virion of the attenuated influenza virus backbone.

In certain embodiments, the TM and CT domains or the TM domain of thefusion protein correspond to the TM and CT domains or the TM domain of adifferent type, subtype or strain of influenza virus than the backboneattenuated influenza virus. In other embodiments, the TM and CT domainsor the TM domain of the fusion protein correspond to the TM and CTdomains or the TM domain of an influenza virus of a species other thanthe backbone attenuated influenza virus. In preferred embodiments, theTM and CT domains or the TM domain of the fusion protein correspond tothe TM and CT domains or the TM domain of the attenuated influenza virusbackbone.

In certain embodiments, the TM and CT domains of the fusion proteincorrespond to the TM and CT domains of either an HA protein or an NAprotein of an influenza virus. Since the CT domain of HA or NA may notbe necessary for incorporation of the fusion protein into the influenzavirus virion, in some embodiments, the fusion protein is engineered tocontain only the TM domain of HA or NA.

The TM and CT domains of influenza virus HA and NA proteins arestructurally distinct in that the domains are located at the C-terminusof the HA protein and the N-terminus of the NA protein. Apart from thediffering orientation of the two domains in each class of surfaceglycoprotein, the HA and CT structural domains may comprise yet unknowndifferences in functionality dependent on their relative placementwithin a polypeptide chain. Therefore, when designing the fusion proteinto be engineered into the attenuated influenza virus, the orientation ofthe ectodomain, or fragment therof, of the infectious agent to be fusedto the TM and CT domains or the TM domain of an influenza virusglycoprotein will guide the selection of the TM and CT domains or the TMdomain.

To maintain viral competence, where a surface glycoprotein is replaced,its function in the chimeric virus must be supplied by the fusionprotein. In one embodiment of the invention, the chimeric attenuatedinfluenza virus comprises a fusion protein that exhibits neuraminidaseactivity. In another embodiment of the invention, the chimericattenuated influenza virus comprises a fusion protein that exhibitsreceptor binding activity. In another embodiment of the invention, thechimeric attenuated virus comprises two fusion proteins, one of whichexhibits neuraminidase activity and the other of which exhibits receptorbinding activity. In still other embodiment of the invention, thechimeric attenuated influenza virus comprises a fusion proteincomprising a fragment of a protein of a heterologous infectious agent,which fusion protein exhibits exhibits neuraminidase activity orreceptor binding activity. In a specific embodiment, the chimericattenuated influenza virus comprises a surface protein containing theectodomain of the HN protein of Newcastle Disease Virus (NDV) and the TMand CT domains of the NA protein of Influenza A/WSN/33, which HNectodomain exhibits neuraminidase activity. In other embodiments, thechimeric attenuated influenza virus comprises a fusion proteincontaining the ectodomain of the HA protein of a heterologous influenzasubtype or strain (e.g., the ectodomain of H7 HA or ectodomain of H9HA).

In certain embodiments, the at least one fusion protein of the chimericattenuated influenza virus of the invention does not comprise thecomplete ectodomain of a heterologous protein (e.g., comprises anantigenic or protective fragment of the ectodomain of a protein of aheterologous infectious agent), and may or may not further comprise oneor more fragments of the ectodomain of a native essential glycoprotein.Accordingly, in certain embodiments, the ectodomain of the fusionprotein may comprise a fragment of the ectodomain of a protein of aheterologous infectious agent. In other embodiments, the ectodomain ofthe fusion protein may comprise fragments of both a native essentialglycoprotein and a protein of a heterologous infectious agent. Inembodiments where the fusion protein replaces an essential surfaceglycoprotein, the function of the surface glycoprotein must be suppliedby the fusion protein, i.e., the fusion protein must exhibit thefunctionality of the surface glycoprotein that it is replacing.

The ectodomain of the fusion proteins described in this Section 5.1.2may correspond to or be derived from any glycoprotein, or fragmentthereof, of an infectious agent (including, viral, bacterial andparasitic infectious agents). Non-limiting examples of infectious agentglycoproteins are provided in Section 5.3, infra.

In certain embodiments, the fusion protein comprises the transmembranedomain plus 1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1 immediatelyadjacent residue(s) of the ectodomain of an essential influenza virusglycoprotein. In a specific embodiment, the fusion protein comprises thetransmembrane domain of an influenza virus NA protein, 1 to 15, 1 to 10,1 to 5, 1 to 3, 2 or 1 immediately adjacent residue(s) of the ectodomainof the influenza virus NA protein, and the ectodomain, or fragmentthereof, of an infectious agent other than influenza virus such that thefusion protein can functionally replace the function of NA protein. Inanother specific embodiment, the fusion protein comprises thecytoplasmic and transmembrane domains of an influenza virus NA protein,1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1 residue(s) of the ectodomain ofthe influenza virus NA protein that are immediately adjacent to thetransmembrane domain of the influenza virus NA protein, and theectodomain, or fragment thereof, of an infectious agent other thaninfluenza virus such that the fusion protein can functionally replacethe NA protein. In another embodiment, the fusion protein comprises thetransmembrane domain or cytoplasmic and transmembrane domains of an NAprotein, the complete stalk domain, or a fragment thereof, of an NAprotein that precedes its globular head, and the ectodomain, or fragmentthereof, of an infectious agent other than influenza virus such that thefusion protein can functionally replace the function of NA protein. Inanother specific embodiment, the fusion protein comprises thetransmembrane domain of an influenza virus HA protein, 1 to 15, 1 to 10,1 to 5, 1 to 3, 2 or 1 immediately adjacent residue(s) of the ectodomainof the influenza virus HA protein, and the ectodomain, or fragmentthereof, of an infectious agent other than influenza virus such that thefusion protein can functionally replace the function of HA protein. Inanother specific embodiment, the fusion protein comprises thecytoplasmic and transmembrane domains of an influenza virus HA protein,1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1 residue(s) of the ectodomain ofthe influenza virus HA protein that are immediately adjacent to thetransmembrane domain of the influenza virus HA protein, and theectodomain, or fragment thereof, of an infectious agent other thaninfluenza virus such that the fusion protein can functionally replacethe HA protein.

The present invention encompasses nucleotide sequences (i.e.,recombinant segments) encoding the fusion proteins described in thisSection 5.1.2. In preferred embodiments, the recombinant segmentscomprising nucleic acids encoding the fusion proteins described inSection 5.1.2 comprise 3′ and 5′ incorporation signals which arerequired for proper replication, transcription and packaging of thevRNAs (Fujii et al., 2003, Proc. Natl. Acad. Sci. USA 100:2002-2007;Zheng, et al., 1996, Virology 217:242-251, both of which areincorporated by reference herein in their entireties). In a preferredembodiment, the recombinant segments of the invention therefore use the3′ and 5′ noncoding and/or nontranslated sequences of segments ofviruses within the same viral type or strain as the backbone attenuatedinfluenza virus. In specific embodiments, the recombinant segmentscomprise nucleic acids encoding the fusion proteins described in Section5.1.2 that comprise the 3′ noncoding region of an influenza virus NAvRNA, the NA coding region corresponding to the CT and TM domains of theNA protein, 1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1 residue(s) of theectodomain of the influenza virus NA protein that are immediatelyadjacent to the transmembrane domain of the influenza virus NA protein,the untranslated regions of the NA protein reading frame and the5′non-coding region of the NA vRNA. In certain embodiments, therecombinant segments comprise nucleic acids encoding the fusion proteinsdescribed in Section 5.1.2 that comprise the complete stalk domain, orfragment thereof, of an NA protein that precedes its globular head.

As an alternative to replacing the NA or HA proteins of an attenuatedinfluenza virus, “reverse genetic” and bicistronic techniques may beused to produce a chimeric influenza virus comprising an ectodomain ofan infectious agent other than influenza virus or a disease antigen andthe TM and/or CT domains of an influenza virus. See, e.g., U.S. Pat. No.6,887,699, U.S. Pat. No. 6,001,634, U.S. Pat. No. 5,854,037 and U.S.Pat. No. 5,820,871, each of which is hereby incorporated by reference inits entirety. Non-limiting examples of heterologous molecules such asdisease antigens and antigens derived from an infectious agent that maybe used in accordance with the methods of the invention (e.g. antigensassociated with a disease or viral proteins) are provided in section5.3, infra.

5.1.3 Chimeric Avian Influenza Viruses Comprising the Ectodomain of theHN Protein of Newcastle Disease Virus

The present invention encompasses the engineering of an avian influenzavirus such that a fusion protein comprising the ectodomain of the HNprotein of Newcastle Disease virus is encoded by the genome and, whenexpressed, is incorporated into the virion. Any avian influenza virustype or strain that can be engineered to express and incorporate thefusion protein into the avian influenza virion can be selected and usedin accordance with the invention including, but not limited to,naturally occurring strains, variants or mutants, mutagenized viruses,reassortants and/or genetically engineered viruses. Non-limitingexamples of avian influenza viruses include Influenza A subtype H5N1,H6N2, H7N3, H9N2 or H10N7.

The present invention provides a chimeric avian influenza virus,comprising a fusion protein having an ectodomain (ED) of a NewcastleDisease virus (NDV) HN protein and the cytoplasmic (CT) andtransmembrane (TM) domains or the transmembrane domain of an influenzavirus NA protein, wherein the fusion protein functionally replaces theavian influenza virus NA protein. In other words, the avian influenzavirus serves as the “backbone” that is engineered to express andincorporate into its virion the fusion protein in place of the avianinfluenza virus NA protein. The inclusion of the TM and CT domains or TMdomain of an influenza virus NA protein in the fusion protein permitsthe fusion protein to incorporate into the virion of the avian influenzavirus. The TM and CT domains or TM domain of the fusion protein maycorrespond to or be derived from any influenza virus that permits thefusion protein to incorporate into the virion of the avian influenzavirus backbone.

The coding sequences of the TM and CT domains for use in accordance withthe invention may be obtained or derived from the published sequence ofany NA protein from any influenza strain or subtype (e.g., GenBank entryAY651447, from strain A/Viet Nam/1203/2004(H5N1); GenBank entry AY96877,from strain A/turkey/Canada/63 (H6N2); GenBank entry AY706954, fromstrain A/duck/Hainan/4/2004 (H6N2); GenBank entry AY646080, from strainA/chicken/British Columbia/GSC_human_B/04 (H7N3); or GenBank entryDQ064434, from strain A/chicken/Beijing/8/98 (H9N2)). In certainembodiments, the TM and CT domains or the TM domain of the fusionprotein correspond to the TM and CT domains or the TM domain of adifferent type or strain of avian influenza virus than the backboneavian influenza virus. In other embodiments, the TM and CT domains orthe TM domain of the fusion protein correspond to the TM and CT domainsor the TM domain of an influenza virus other than an avian influenzavirus. In preferred embodiments, the TM and CT domains or the TM domainof the fusion protein correspond to the TM and CT domains or the TMdomain of the avian influenza virus backbone. In a specific embodiment,TM and CT domains of the fusion protein correspond to the TM and CTdomains of the NA protein of Influenza A/WSN/33.

In certain embodiments, the fusion protein comprises the transmembranedomain of an influenza virus NA protein, 1 to 15, 1 to 10, 1 to 5, 1 to3, 2 or 1 immediately adjacent residue(s) of the ectodomain of theinfluenza virus NA protein, and the ectodomain of a NDV HN protein. Inanother specific embodiment, the fusion protein comprises thecytoplasmic and transmembrane domains of an influenza virus NA protein,1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1 residue(s) of the ectodomain ofthe influenza virus NA protein that are immediately adjacent to thetransmembrane domain of the influenza virus NA protein, and theectodomain of a NDV HN protein. In another specific embodiment, thefusion protein comprises the complete stalk domain, or a fragmentthereof, of an NA protein that precedes its globular head and theectodomain of a NDV HN protein. In other specific embodiments, thefusion protein comprises the transmembrane domain or cytoplasmic andtransmembrane domains of an NA protein, and further comprises thecomplete stalk domain, or a fragment thereof, of an NA protein thatprecedes its globular head and the ectodomain of a NDV HN protein.

As an alternative to replacing the NA protein of avian influenza virus,“reverse genetic” and bicistronic techniques may be used to produce achimeric avian influenza virus comprising an ectodomain of a NDV HNprotein and the TM and/or CT domains of an influenza virus. See, e.g.,U.S. Pat. No. 6,887,699, U.S. Pat. No. 6,001,634, U.S. Pat. No.5,854,037 and U.S. Pat. No. 5,820,871, each of which is herebyincorporated by reference in its entirety.

The present invention encompasses nucleotide sequences (i.e.,recombinant segments) encoding the fusion proteins described in thisSection 5.1.3. In preferred embodiments, the recombinant segmentscomprising nucleic acids encoding the fusion proteins described inSection 5.1.3 comprise 3′ and 5′ incorporation signals which arerequired for proper replication, transcription and packaging of thevRNAs (Fujii et al., 2003, Proc. Natl. Acad. Sci. USA 100:2002-2007;Zheng, et al., 1996, Virology 217:242-251, both of which areincorporated by reference herein in their entireties). In a preferredembodiment, the recombinant segments of the invention therefore use the3′ and 5′ noncoding and/or nontranslated sequences of segments ofviruses within the same viral type or strain as the backbone avianinfluenza virus. In specific embodiments, the recombinant segmentcomprises nucleic acids encoding the fusion proteins described inSection 5.1.3 comprise the 3′ noncoding region of an influenza virus NAvRNA, the NA coding region corresponding to the CT and TM domains of theNA protein, 1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1 residue(s) of theectodomain of the influenza virus NA protein that are immediatelyadjacent to the transmembrane domain of the influenza virus NA protein,the untranslated regions of the NA protein reading frame and the 5′non-coding region of the NA vRNA. In another specific embodiment, arecombinant segment comprises, 3′ to 5′ order, the 3′ noncoding regionof the WSN NA vRNA (19 nucleotides), nucleotides encoding amino acidresidues 1-36 (108 nucleotides) of the NA coding region, nucleotidesencoding amino acid residues 51-568 of the NDV B1 HN protein, twosequential stop codons, 157 nucleotides of the WSN NA untranslatedreading frame, and the 5′ noncoding region of the WSN vRNA (28nucleotides). See FIG. 1.

Replacement of the NA protein of the backbone influenza virus orintroduction of a recombinant segment into the viral genome mayattenuate the resulting chimeric virus, i.e., the chimeric virus willexhibit impaired replication relative to wild type. In certainembodiments of the invention, attenuation of the chimeric virus isdesired such that the chimeric virus remains, at least partially,infectious and can replicate in vivo, but only generate low titersresulting in subclinical levels of infection that are non-pathogenic.Such attenuated chimeric viruses are especially suited for embodimentsof the invention wherein the virus is administered to a subject in orderto act as an immunogen, e.g., a live vaccine. The viruses may beattenuated by any method known in the art and/or exemplified herein,e.g., engineering the virus to comprise a mutation in the NS1 gene or tocomprise a modification in the polybasic amino acid sequence before thecleavage site in the HA protein (see U.S. Pat. No. 6,468,544; U.S. Pat.No. 6,669,943; Li et al., J. Infect. Dis. 179:1132-1138, each of whichis hereby incorporated by reference in its entirety).

In one embodiment, an attenuated chimeric avian influenza virus of theinvention comprises a genome comprising a mutation in the NS1 gene ofthe avian influenza backbone virus, which is known in other influenzaviruses to diminishes the ability of the NS1 gene product to antagonizea cellular interferon response. In another embodiment, an attenuatedchimeric avian influenza virus of the invention comprises a genomecomprising a mutation in the HA gene of the avian influenza backbonevirus, which is known in other influenza viruses to diminishes oreliminates the ability of cellular proteases to cleave the protein intoits active form and thereby reduce or eliminate HA induced fusion andinfectivity. In yet another embodiment, an attenuated chimeric avianinfluenza virus of the invention comprises a genome comprising amutation in both the HA gene and NS1 gene of the avian influenzabackbone virus, which are known in other influenza viruses to eitherseparately or when combined to reduce or diminish viral activity. Thetiters of attenuated-chimeric and wild-type avian influenza viruses canbe determined utilizing any technique well-known in the art or describedherein, (e.g., hemagglutination assays, plaque assays, egg infectiousdoses (EID50), tissue culture infectious doses (TCID50), etc.) and theviruses can be propagated under conditions described herein orwell-known in the art (e.g., in CEF cells, MDCK cells (e.g., in MEM, 10%v/v fetal calf serum (FCS), 1% penicillin/streptomycin at 37° C. in a 5%CO₂ humidified incubator) or embryonated chicken eggs (e.g., in astationary incubator at 37° C. with 55% relative humidity).Alternatively, the viruses can be propagated in cells (e.g., CEF cells,MDCK cells, etc.) that are grown in serum-free or serum reduced (e.g.,TPCK trypsin) medium.

5.2 Chimeric Newcastle Disease Virus

The present invention encompasses the engineering of an NewcastleDisease Virus (“NSV”) such that at least one fusion protein is encodedby the genome and, when expressed, is incorporated into the virion. AnyNDV type or strain that can be engineered to express and incorporate theat least one fusion protein into the NDV virion can be selected and usedin accordance with the invention including, but not limited to,naturally occurring strains, variants or mutants, mutagenized viruses,reassortants and/or genetically engineered viruses. In a specificembodiment, the NDV is a naturally occurring virus. In another specificembodiment, the NDV is a genetically engineered virus. For example, asdescribed herein, mutant strains of the recombinant NDV, rNDV/F2aa andrNDV/F3aa, in which the cleavage site of the F protein was replaced withone containing one or two extra arginine residues, allowing the mutantcleavage site to be activated by ubiquitously expressed proteases of thefurin family can be used in accordance with the methods of theinvention. Non-limiting examples of ND Vs which may be used inaccordance with the methods of the invention include B1, LaSota, YG97,MET95, and F48E9. In a specific embodiment, the chimeric NDV or rNDV ofthe invention comprises a fusion protein containing the ectodomain of aninfluenza HA protein; in a specific example in accordance with thisembodiment the influenza HA protein is the HA protein from influenza H7.

The present invention provides a chimeric NDV, comprising at least onefusion protein having an ectodomain (ED), or fragment thereof, of aprotein of an infectious agent other than a NDV protein and thecytoplasmic (CT) and/or transmembrane (TM) domains of an essential NDVglycoprotein. The present invention also provides a chimeric NDV,comprising at least one fusion protein having an ED, or fragmentthereof, and TM domain of a protein of an infectious agent other than aNDV glycoprotein and the CT of an essential NDV glycoprotein. Thepresent invention further provides a chimeric NDV, comprising a fusionprotein having an ED, or fragment thereof, and CT domain of a protein ofan infectious agent other than a NDV glycoprotein and a TM domain of anessential NDV glycoprotein. In other words, the NDV virus serves as the“backbone” that is engineered to express and incorporate into its virionthe fusion protein. The inclusion of the TM and/or CT domains of anessential NDV glycoprotein in the fusion protein permits the fusionprotein to incorporate into the virion of the NDV. The TM and/or CTdomains of the fusion protein may correspond to or be derived from anyNDV that permits the fusion protein to incorporate into the virion ofthe NDV backbone.

In certain embodiments, the TM and/or CT domains of the fusion proteincorrespond to the TM and/or CT domains of a different type or strain ofNDV than the backbone NDV. In preferred embodiments, the TM and/or CTdomains of the fusion protein correspond to the TM and/or CT domains ofthe NDV backbone.

The NDV virion comprises two major surface glycoproteins: fusion protein(F) and hemagglutinin-neuraminidase (HN), both of which comprise acytoplasmic domain, a transmembrane domain and an ectodomain.Accordingly, in certain embodiments, the TM and/or CT domains of thefusion protein correspond to the TM and/or CT domains of either an Fprotein or an HN protein of an NDV.

The TM and CT domains of NDV F and HN proteins are structurally distinctin that the domains are located at the C-terminus of the F protein andthe N-terminus of the HN protein. Therefore, when designing the fusionprotein to be engineered into the NDV, the orientation of the ectodomainof the infectious agent to be fused to the TM and/or CT domains of NDVglycoprotein will guide the selection of the TM and/or CT domains.

In certain embodiments the at least one fusion protein of the chimericNDV comprises the TM domain and 1 to 15, 1 to 10, 1 to 5, 1 to 3, 2 or 1immediately adjacent residues of the ectodomain of an essential NDVglycoprotein. For example, in a specific embodiment, the fusion proteincomprises the transmembrane domain of an NDV F protein, 1 to 15, 1 to10, 1 to 5, 1 to 3, 2 or 1 immediately adjacent residue(s) of theectodomain of the NDV F protein, and the ectodomain, or fragmentthereof, of an infectious agent other than NDV such that the fusionprotein can functionally replace the function of F protein. In anotherspecific embodiment, the fusion protein comprises the cytoplasmic andtransmembrane domains of a NDV F protein, 1 to 15, 1 to 10, 1 to 5, 1 to3, 2 or 1 residue(s) of the ectodomain of the NDV F protein that areimmediately adjacent to the transmembrane domain of the NDV F protein,and the ectodomain, or fragment thereof, of an infectious agent otherthan NDV such that the fusion protein can functionally replace the Fprotein. In another specific embodiment, the fusion protein comprisesthe transmembrane domain of an NDV HN protein, 1 to 15, 1 to 10, 1 to 5,1 to 3, 2 or 1 immediately adjacent residue(s) of the ectodomain of theNDV HN protein, and the ectodomain, or fragment thereof, of aninfectious agent other than NDV such that the fusion protein canfunctionally replace the function of HN protein. In another specificembodiment, the fusion protein comprises the cytoplasmic andtransmembrane domains of an NDV HN protein, 1 to 15, 1 to 10, 1 to 5, 1to 3, 2 or 1 residue(s) of the ectodomain of the NDV HN protein that areimmediately adjacent to the transmembrane domain of the NDV HN protein,and the ectodomain, or fragment thereof, of an infectious agent otherthan NDV such that the fusion protein can functionally replace the HNprotein.

In certain embodiments, an NDV surface glycoprotein (i.e., HN or Fprotein) is replaced by a fusion protein that supplies the requiredfunction(s) of the NDV glycoprotein. In accordance with theseembodiments, the ectodomain of the fusion protein must be selected sothat it will supply the required function(s) of the replaced NDVglycoprotein. In other embodiments, the fusion protein is expressed andincorporated into the virion of the NDV in addition to the native NDVsurface glycoproteins.

In certain embodiments, the at least one fusion protein of the chimericNDV of the invention does not comprise the complete ectodomain of aheterologous protein (e.g., comprises an antigenic fragment of theectodomain of a protein of a heterologous infectious agent), and may ormay not further comprise one or more fragments of the ectodomain of anative essential glycoprotein. Accordingly, in certain embodiments, theectodomain of the fusion protein may comprise a fragment of theectodomain of a protein of a heterologous infectious agent. In otherembodiments, the ectodomain of the fusion protein may comprise fragmentsof both a native essential glycoprotein and a protein of a heterologousinfectious agent. In embodiments where the fusion protein replaces anessential surface glycoprotein, the function of the surface glycoproteinmust be supplied by the fusion protein, i.e., the fusion protein mustexhibit the functionality of the surface glycoprotein that it isreplacing.

Provided that the fusion protein described in this Section 5.2 is notrequired to replace the function of a necessary viral glycoprotein, theectodomain of the fusion protein may correspond to or be derived fromany heterologous molecule including, but not limited to, any infectiousagent antigen (including, viral, bacterial and parasitic infectiousagent antigens), and any disease antigen. Non-limiting examples ofinfectious agent antigens and/or disease antigens are provided inSection 5.3, infra.

The present invention encompasses nucleotide sequences encoding thefusion proteins described in this Section 5.2. In specific embodiments,a nucleotide sequence comprises nucleic acids encoding a Kozak sequence,followed by the gene end, intercistronic nucleotide (T), and gene startsequence of the F protein of NDV, followed by the 5′ untranslated regionand ORF of the HA protein of H7N2.

In preferred embodiments, the strains of NDV used in accordance with theinvention are the lentogenic stains of the virus, i.e., those strainswhich typically exhibit low virulence or asymptomatic infection inavians, e.g., strain B1, strain LaSota or strain Met95. The inventionalso encompasses the use of highly virulent stains of NDV, e.g., YG97 orF48E9 or NDV strains that have been modified by genetic recombinationusing methods known in the art or exemplified herein. In a specificembodiment, the invention encompasses the use of an NDV wherein the NDVF protein has been genetically modified at the cleavage site so as toincrease fusogenic activity. In a specific example in accordance withthis invention, the modified F protein comprises two to three amino acidmutations at the F cleavage site. Replacement of a necessary surfaceprotein of the backbone virus or introduction of a nucleotide sequenceencoding a fusion protein into the viral genome may attenuate, orfurther attenuate, the resulting chimeric virus, i.e., the chimericvirus will exhibit impaired replication relative to wild type. Incertain embodiments of the invention, attenuation, or furtherattenuation, of the chimeric virus is desired such that the chimericvirus remains, at least partially, infectious and can replicate in vivo,but only generate low titers resulting in subclinical levels ofinfection that are non-pathogenic. Such attenuated chimeric viruses areespecially suited for embodiments of the invention wherein the virus isadministered to a subject in order to act as an immunogen, e.g., a livevaccine. The viruses may be attenuated by any method known in the art.

5.3 Antigens that May be Engineered in to the Chimeric Viruses of theInvention

In accordance with the invention, any heterologous molecule can beengineered into the virus backbone to elicit an immune response to saidmolecule. In a specific embodiment, any antigen of any infectiouspathogen or associated with any disease that is capable of eliciting animmune response may be engineered into a NDV and/or influenza virusbackbone. In a specific embodiment, the antigen is a glycoprotein. Incertain preferred embodiments, the antigen is capable of functionallyreplacing an essential glycoprotein of an influenza virus and/or NDV. Inspecific embodiments, the antigen exhibits neuraminidase orhemagglutinin (e.g., receptor binding/fusogenic) activities. Inselecting the viral backbone to express the antigen, the orientation ofthe nucleotide encoding the antigen is considered. For example, wherethe antigen is naturally anchored via its amino-terminus, the TM and CTdomains or the TM domain for use in engineering the fusion protein willcorrespond to the TM and CT domains or the TM domain of a necessaryviral protein of the backbone virus, or related virus, which is alsonaturally anchored via its amino terminus, e.g., the N protein ofinfluenza or the HN protein of NDV.

In a specific embodiment, a viral antigen is engineered into a NDV orinfluenza virus backbone. Nonlimiting examples of viral antigens includeantigens from adenoviridae (e.g., mastadenovirus and aviadenovirus),herpesviridae (e.g., herpes simplex virus 1, herpes simplex virus 2,herpes simplex virus 5, herpes simplex virus 6, Epstein-Barr virus,HEIV6-HHV8 and cytomegalovirus), leviviridae (e.g., levivirus,enterobacteria phase MS2, allolevirus), poxviridae (e.g.,chordopoxvirinae, parapoxvirus, avipoxvirus, capripoxvirus,leporiipoxvirus, suipoxvirus, molluscipoxvirus, and entomopoxvirinae),papovaviridae (e.g., polyomavirus and papillomavirus), paramyxoviridae(e.g., paramyxovirus, parainfluenza virus 1, mobillivirus (e.g., measlesvirus), rubulavirus (e.g., mumps virus), pneumonovirinae (e.g.,pneumovirus, human respiratory synctial virus), human respiratorysyncytial virus and metapneumovirus (e.g., avian pneumovirus and humanmetapneumovirus)), picornaviridae (e.g., enterovirus, rhinovirus,hepatovirus (e.g., human hepatits A virus), cardiovirus, andapthovirus), reoviridae (e.g., orthoreovirus, orbivirus, rotavirus,cypovirus, fijivirus, phytoreovirus, and oryzavirus), retroviridae(e.g., mammalian type B retroviruses, mammalian type C retroviruses,avian type C retroviruses, type D retrovirus group, BLV-HTLVretroviruses, lentivirus (e.g. human immunodeficiency virus 1 and humanimmunodeficiency virus 2 (e.g., HIV gp160), spumavirus), flaviviridae(e.g., hepatitis C virus, dengue virus, West Nile virus), hepadnaviridae(e.g., hepatitis B virus), togaviridae (e.g., alphavirus (e.g., sindbisvirus) and rubivirus (e.g., rubella virus)), rhabdoviridae (e.g.,vesiculovirus, lyssavirus, ephemerovirus, cytorhabdovirus, andnecleorhabdovirus), arenaviridae (e.g., arenavirus, lymphocyticchoriomeningitis virus, Ippy virus, and lassa virus), and coronaviridae(e.g., coronavirus and torovirus). In a specific embodiment the viralantigen, is HIV gp120, HIV nef, RSV F glycoprotein, RSV G glycoprotein,influenza virus neuraminidase, influenza virus hemagglutinin, HTLV tax,herpes simplex virus glycoprotein (e.g., gB, gC, gD, and gE) orhepatitis B surface antigen, hepatitis C virus E protein or coronavirusspike protein. In certain embodiments, the viral antigen is not gp 41.In certain embodiments, the viral antigen is derived from aparamyxovirus. In other, alternative embodiments, the viral antigen isnot derived from a paramyxovirus. In certain embodiments, the viralantigen is derived from human parainfluenza virus type 1, humanparainfluenza virus types 3, a RSV or from Sendai virus In other,alternative, embodiments, the viral antigen is not derived from humanparainfluenza virus type 1, parainfluenza virus type 3, a RSV or fromSendai virus. In specific embodiments, the virus backbone is aninfluenza virus and the antigen engineered into the influenza virusbackbone is not an influenza antigen. In other specific embodiments, thevirus backbone is an NDV and the antigen engineered into the NDVbackbone is not an NDV antigen.

In another embodiment, a bacterial antigen (e.g., bacterial coat proteinor protective antigen associated with said bacteria) is engineered intoa NDV or influenza virus backbone. Nonlimiting examples of bacterialantigens include antigens from bacteria of the Aquaspirillum family,Azospirillum family, Azotobacteraceae family, Bacteroidaceae family,Bartonella species, Bdellovibrio family, Campylobacter species,Chlamydia species (e.g., Chlamydia pneumoniae), clostridium,Enterobacteriaceae family (e.g., Citrobacter species, Edwardsiella,Enterobacter aerogenes, Erwinia species, Escherichia coli, Hafniaspecies, Klebsiella species, Morganella species, Proteus vulgaris,Providencia, Salmonella species, Serratia marcescens, and Shigellaflexneri), Gardinella family, Haemophilus influenzae, Halobacteriaceaefamily, Helicobacter family, Legionallaceae family, Listeria species,Methylococcaceae family, mycobacteria (e.g., Mycobacteriumtuberculosis), Neisseriaceae family, Oceanospirillum family,Pasteurellaceae family, Pneumococcus species, Pseudomonas species,Rhizobiaceae family, Spirillum family, Spirosomaceae family,Staphylococcus (e.g., methicillin resistant Staphylococcus aureus andStaphylococcus pyrogenes), Streptococcus (e.g., Streptococcusenteritidis, Streptococcus fasciae, and Streptococcus pneumoniae),Vampirovibr Helicobacter family, Yersinia family, Bacillus antracis andVampirovibrio family.

In other embodiments, a protective antigen associated with a parasite(e.g. a protozoan) is engineered into a NDV or influenza virus backbone.Any antigen associated with a parasite or protective antigen of aparasite (e.g., a protozoan) may be used in accordance with the methodsof the invention. Nonlimiting examples of parasite antigens includeantigens from a parasite such as an amoeba, a malarial parasite,Plasmodium, Trypanosoma cruzi.

In another embodiment, a fungal antigen is engineered into a NDV orinfluenza virus backbone. Nonlimiting examples of fungal antigensinclude antigens from fungus of Absidia species (e.g., Absidiacorymbifera and Absidia ramosa), Aspergillus species, (e.g., Aspergillusflavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger,and Aspergillus terreus), Basidiobolus ranarum, Blastomycesdermatitidis, Candida species (e.g., Candida albicans, Candida glabrata,Candida kerr, Candida krusei, Candida parapsilosis, Candidapseudotropicalis, Candida quillermondii, Candida rugosa, Candidastellatoidea, and Candida tropicalis), Coccidioides immitis,Conidiobolus species, Cryptococcus neoforms, Cunninghamella species,dermatophytes, Histoplasma capsulatum, Microsporum gypseum, Mucorpusillus, Paracoccidioides brasiliensis, Pseudallescheria boydii,Rhinosporidium seeberi, Pneumocystis carinii, Rhizopus species (e.g.,Rhizopus arrhizus, Rhizopus oryzae, and Rhizopus microsporus),Saccharomyces species, Sporothrix schenckii, zygomycetes, and classessuch as Zygomycetes, Ascomycetes, the Basidiomycetes, Deuteromycetes,and Oomycetes.

In another embodiment, a tumor associated antigen is engineered into aNDV or influenza virus backbone. Any tumor associated antigen known inthe art may be used in accordance with the methods of the invention.Nonlimiting examples of tumor associated antigens include MAGE-1,MAGE-3, BAGE, GAGE-1, GAGE-2, N-acetylglucosaminyltransferase-V, p-15,MART-1/MelanA, TRP-1 (gp75), Tyrosinase, cyclin-dependent kinase 4,β-catenin, MUM-1, CDK4, HER-2/neu, human papillomavirus-E6, humanpapillomavirus E7, MUC-1, caspase-8, CD5, CD20, CEA, mucin-1, Lewis^(x),CA-125, epidermal growth factor receptor, p185^(HER2), IL-2R, Fap-α,tenascin, antigens associated with a metalloproteinase, and CAMPATH-1.

5.4 Construction and Propagation of Chimeric Viruses of the Invention

The chimeric viruses of the invention can be generated using the reversegenetics technique. The reverse genetics technique involves thepreparation of synthetic recombinant viral RNAs that contain thenon-coding regions of the negative-strand, viral RNA which are essentialfor the recognition by viral polymerases and for packaging signalsnecessary to generate a mature virion. The recombinant RNAs aresynthesized from a recombinant DNA template and reconstituted in vitrowith purified viral polymerase complex to form recombinantribonucleoproteins (RNPs) which can be used to transfect cells. A moreefficient transfection is achieved if the viral polymerase proteins arepresent during transcription of the synthetic RNAs either in vitro or invivo. The synthetic recombinant RNPs can be rescued into infectiousvirus particles. The foregoing techniques are described in U.S. Pat. No.5,166,057 issued Nov. 24, 1992; in U.S. Pat. No. 5,854,037 issued Dec.29, 1998; in European Patent Publication EP 0702085A1, published Feb.20, 1996; in U.S. patent application Ser. No. 09/152,845; inInternational Patent Publications PCT WO97/12032 published Apr. 3, 1997;WO96/34625 published Nov. 7, 1996; in European Patent Publication EPA780475; WO 99/02657 published Jan. 21, 1999; WO 98/53078 published Nov.26, 1998; WO 98/02530 published Jan. 22, 1998; WO 99/15672 publishedApr. 1, 1999; WO 98/13501 published Apr. 2, 1998; WO 97/06270 publishedFeb. 20, 1997; and EPO 780 475A1 published Jun. 25, 1997, each of whichis incorporated by reference herein in its entirety.

The helper-free plasmid technology can also be utilized to engineer achimeric virus of the invention. Briefly, with respect to influenzavirus, full length cDNAs of viral segments are amplified using PCR withprimers that include unique restriction sites, which allow the insertionof the PCR product into the a plasmid vector (Flandorfer et al., 2003,J. Virol. 77:9116-9123; Nakaya et al., 2001, J. Virol. 75:11868-11873;both of which are incorporated herein by reference in their entireties).The plasmid vector is designed to position the PCR product between atruncated human RNA polymerase I promoter and a hepatitis delta virusribozyme sequence such that an exact negative (vRNA sense) transcript isproduced from the polymerase I promoter. Separate plasmid vectorscomprising each viral segment as well as expression vectors comprisingnecessary viral proteins are transfected into cells leading toproduction of recombinant viral particles. For a detailed description ofhelper-free plasmid technology see, e.g., International Publication No.WO 01/04333; U.S. Pat. No. 6,649,372; Fodor et al., 1999, J. Virol.73:9679-9682; Hoffmann et al., 2000, Proc. Natl. Acad. Sci. USA97:6108-6113; and Neumann et al., 1999, Proc. Natl. Acad. Sci. USA96:9345-9350, which are incorporated herein by reference in theirentireties. Similarly, with respect to the single segment genome of NDV,a complete cDNA of the Hitchner B1 strain was constructed, inserted intoa plasmid vector and engineered to containing a unique restriction sitebetween the P and M genes. The fusion protein engineered in accordancewith the invention may then be inserted into the viral genome at theunique restriction site. The single segment was positioned between a T7promoter and the hepatitis delta virus ribozyme to produce an exactnegative transcript from the T7 polymerase. The plasmid vector andexpression vectors comprising the necessary viral proteins aretransfected into cells leading to production of recombinant viralparticles (see Swayne et al., 2003, Avian Dis. 47:1047-1050 and Swayneet al., 2001, J. Virol. 11868-11873, each of which is incorporated byreference in its entirety).

The chimeric influenza viruses of the invention can be engineered tocontain RNA segments which are bicistronic. Bicistronic techniques allowthe engineering of coding sequences of multiple proteins into a singlemRNA through the use of IRES sequences. IRES sequences direct theinternal recruitment of ribozomes to the RNA molecule and allowdownstream translation in a cap independent manner. Briefly, an codingregion of one protein is inserted into the ORF of a second protein. Theinsertion is flanked by an IRES and any untranslated signal sequencesnecessary for proper expression and/or function. The insertion must notdisrupt the open reading frame, polyadenylation or transcriptionalpromoters of the second protein (see e.g., Garcia-Sastre et al., 1994,J. Virol. 68:6254-6261 and Garcia-Sastre et al., 1994 Dev. Biol. Stand.82:237-246), each of which is hereby incorporated by reference in itsentirety.

5.4.1 Propagation of Chimeric Viruses

The chimeric influenza viruses of the present invention can bepropagated in any substrate that allows the virus to grow to titers thatpermit the uses of the chimeric viruses described herein. In oneembodiment, the substrate allows the chimeric viruses to grow to titerscomparable to those determined for the corresponding wild-type viruses.In a specific embodiment, the attenuated chimeric influenza viruses ofthe invention are propagated in IFN-deficient substrates.

The chimeric viruses of the invention may be grown in cells (e.g. aviancells, chicken cells, etc.) that are susceptible to infection by theviruses, embryonated eggs or animals (e.g., birds). Such methods arewell-known to those skilled in the art. In a specific embodiment, thecells used to propagate attenuated influenza viruses with a reducedinterferon antagonist activity are IFN-deficient. In one embodiment, thechimeric avian viruses of the invention are propagated in chicken cellsor embryonated eggs. Representative chicken cells include, but are notlimited to, chicken embryo fibroblasts or chicken embryo kidney cells.

Chimeric viruses of the invention may be propagated in embryonated eggs,e.g., from 6 to 14 days old. Young or immature embryonated eggs can beused to propagate attenuated chimeric influenza viruses of theinvention. Immature embryonated eggs encompass eggs which are less thanten day old eggs, e.g., eggs 6 to 9 days that are INF-deficient.Immature embryonated eggs also encompass eggs which artificially mimicimmature eggs up to, but less than ten day old, as a result ofalterations to the growth conditions, e.g., changes in incubationtemperatures; treating with drugs; or any other alteration which resultsin an egg with a retarded development, such that the IFN system is notfully developed as compared with ten to twelve day old eggs. Thechimeric viruses of the invention can be propagated in differentlocations of the embryonated egg, e.g., the allantoic cavity. For adetailed discussion on the growth and propagation viruses, in particularattenuated influenza viruses with at reduced interferon antagonistactivity see, e.g., U.S. Pat. No. 6,852,522 and U.S. Pat. No. 6,852,522,both of which are hereby incorporated by reference in their entireties.

For virus isolation, the chimeric virus is removed from cell culture andseparated from cellular components, typically by well knownclarification procedures, e.g., such as gradient centrifugation andcolumn chromatography, and may be further purified as desired usingprocedures well known to those skilled in the art, e.g., plaque assays.

5.5 Uses of Chimeric Viruses

The chimeric viruses of the invention can be used in active immunizationin a subject. In one aspect, the chimeric viruses of the invention canbe used to prevent, manage and or treat one or more diseases. In aspecific aspect, the chimeric viruses of the invention can be used toprevent, manage and/or treat infections by two infectious agents. SeeSection 5.5.1 for a description of immunogenic formulation and uses ofthose formulations for inducing an immune response in a subject. Thechimeric viruses of the invention can also be used to produce antibodieswhich can be used in diagnostic immunoassays, passive immunotherapy, andgeneration of antiidiotypic antibodies. For example, a chimericinfluenza virus comprising a fusion protein having an ectodomain of aninfectious agent other than an influenza virus can be administered to asubject (e.g., a mouse, rat, pig, horse, donkey, bird or human) togenerate antibodies to both the influenza backbone and the infectiousagent which can then be isolated and used in diagnostic assays, passiveimmunotherapy and generation of antiidiotypic antibodies. The generatedantibodies may be isolated by standard techniques known in the art(e.g., immunoaffinity chromatography, centrifugation, precipitation,etc.) and used in diagnostic immunoassays, passive immunotherapy andgeneration of antiidiotypic antibodies. The isolated antibodies beforebeing used in passive immunotherapy may be modified, e.g., theantibodies may be chimerized or humanized. See, e.g., U.S. Pat. Nos.4,444,887 and 4,716,111; and International Publication Nos. WO 98/46645,WO 98/50433, WO 98/24893, WO98/16654, WO 96/34096, WO 96/33735, and WO91/10741, each of which is incorporated herein by reference in itsentirety, for reviews on the generation of chimeric and humanizedantibodies.

For antibodies produced by the chimeric viruses for use in passiveimmunization, the dosage administered to a subject is typically 0.0001mg/kg to 100 mg/kg of the patient's body weight. Preferably, the dosageadministered to a patient is between 0.0001 mg/kg and 20 mg/kg, 0.0001mg/kg and 10 mg/kg, 0.0001 mg/kg and 5 mg/kg, 0.0001 and 2 mg/kg, 0.0001and 1 mg/kg, 0.0001 mg/kg and 0.75 mg/kg, 0.0001 mg/kg and 0.5 mg/kg,0.0001 mg/kg to 0.25 mg/kg, 0.0001 to 0.15 mg/kg, 0.0001 to 0.10 mg/kg,0.001 to 0.5 mg/kg, 0.01 to 0.25 mg/kg or 0.01 to 0.10 mg/kg of thesubject's body weight. The antibodies encompassed by the invention maybe administered with other prophylactic or therapeutic compositions forthe immunization again or treatment, management or prevention of aninfectious disease or condition, or symptom thereof. Administration ofdoses antibodies of the invention may be by bolus injection or providedmore slowly by IV (e.g., over about 5 minutes, about 15 minutes, about30 minutes, about 45 minutes, about 1 hour, about 2 hours, about 4hours, or about 6 hours). Dosages of the antibodies of the invention mayalso repeated (e.g., every day, every 2 days, every 3 days, every week,every 2 weeks, every 3 weeks, every 6 weeks, every 9 weeks, every 12weeks, every 4 months, every 6 months, every 12 months, every 18 months,or every 2 years) over the course of treatment (e.g., 2 weeks, 1 month,2 months, 4 months, 6 months, 8 months, 10 months, 12 months, 16 months,20 months, or 24 months or longer). In certain embodiments, theantibodies produced by the chimeric viruses of the invention may beadministered parenterally, for example, intravenously, intramuscularlyor subcutaneously, or, alternatively, are administered orally orintranasally. The antibodies encompassed by the invention may also beadministered as a sustained release formulation.

The antibodies isolated from subjects administered a chimeric virus ofthe invention may also be used to monitor treatment and/or diseaseprogression. Any immunoassay system known in the art may be used forthis purpose including but not limited to competitive and noncompetitiveassay systems using techniques such as radioimmunoassays, ELISA (enzymelinked immunosorbent assays), “sandwich” immunoassays, precipitinreactions, gel diffusion precipitin reactions, immunodiffusion assays,agglutination assays, complement fixation assays, immunoradiometricassays, fluorescent immunoassays, protein A immunoassays andimmunoelectrophoresis assays, to name but a few.

The antibodies generated by the chimeric viruses of the invention canalso be used in the production of antiidiotypic antibody. Theantiidiotypic antibody can then in turn be used for immunization, inorder to produce a subpopulation of antibodies that bind an initialantigen of chimeric influenza (Jerne, 1974, Ann. Immunol. (Paris)125c:373; Jerne et al., 1982, EMBO J. 1:234).

In immunization procedures, the amount of immunogen to be used and theimmunization schedule will be determined by a physician skilled in theart and will be administered by reference to the immune response andantibody titers of the subject.

5.5.1 Immunogenic Formulations

The invention also encompasses the use of the chimeric viruses of theinvention in immunogenic formulations, e.g., vaccine formulations. Incases where the immunogenic formulations comprise a chimeric influenzavirus, the formulations may be used in methods of preventing, managing,neutralizing, treating and/or ameliorating influenza virus infection,and/or infections by another infectious agent and/or a disease. In caseswhere the immunogenic formulations comprise a chimeric NDV, theformulations may be used in methods of preventing, managing,neutralizing, treating and/or ameliorating an NDV infection, infectionsby another infectious agent and/or a disease.

The immunogenic formulations may comprise either a live or inactivatedchimeric virus of the invention. The chimeric virus can be inactivatedby methods well known to those of skill in the art. Common methods useformalin and heat for inactivation. See, e.g., U.S. Pat. No. 6,635,246,which is herein incorporated by reference in its entirety. Other methodsinclude those described in U.S. Pat. Nos. 5,891,705; 5,106,619 and4,693,981, herein incorporated by reference in their entireties.

A live immunogenic formulation may be preferred because multiplicationin the subject leads to a prolonged stimulus of similar kind andmagnitude to that occurring in natural infections, and therefore,confers substantial, long lasting immunity. Production of such liverecombinant immunogenic formulations may be accomplished usingconventional methods involving propagation of the chimeric virus in cellculture or in embryonated eggs (e.g., chick embryonated eggs) followedby purification. Moreover, the chimeric viruses can induce a robust IFNresponse which has other biological consequences in vivo, affordingprotection against subsequent infections.

In a preferred embodiment, the immunogenic formulations of the presentinvention comprise an effective amount of a chimeric virus of theinvention, and a pharmaceutically acceptable carrier. The term“pharmaceutically acceptable” means approved by a regulatory agency ofthe Federal or a state government or listed in the U.S. Pharmacopeia orother generally recognized pharmacopeiae for use in animals, and moreparticularly in humans. The term “carrier” refers to a diluent,adjuvant, excipient, or vehicle with which the pharmaceuticalcomposition (e.g., immunogenic or vaccine formulation) is administered.Saline solutions and aqueous dextrose and glycerol solutions can also beemployed as liquid carriers, particularly for injectable solutions.Suitable excipients include starch, glucose, lactose, sucrose, gelatin,malt, rice, flour, chalk, silica gel, sodium stearate, glycerolmonostearate, talc, sodium chloride, dried skim milk, glycerol,propylene, glycol, water, ethanol and the like. Examples of suitablepharmaceutical carriers are described in “Remington's PharmaceuticalSciences” by E. W. Martin. The formulation should suit the mode ofadministration. The particular formulation may also depend on whetherthe chimeric virus is live or inactivated.

The immunogenic formulations of the invention may be administered to anave subject, i.e., a subject that does not have a disease or has notbeen and is not currently infected with one or both infectious agents.In one embodiment, the immunogenic formulations are administered to anave subject, i.e., a subject that does not have a disease or has notbeen and is not currently infected with one or both infectious agents,but is at risk of acquiring such disease (e.g., a viral infection). Inone embodiment, the immunogenic formulations of the invention areadministered to a subject that does not have a disease, or has not andis not infected with one of the infectious agents to which the chimericvirus induces an immune response. In another embodiment, the immunogenicformulations of the invention are administered to a subject that has notand is not infected with both of the infectious agents to which thechimeric virus induces an immune response. The immunogenic formulationsof the invention may also be administered to a subject that is and/orhas been infected with one or both of the infectious agents or anothertype, subtype or strain of the agents to which the chimeric virusinduces an immune response.

Many methods may be used to introduce the immunogenic formulations,e.g., vaccine formulations described above, these include but are notlimited to intranasal, intratracheal, oral, intradermal, intramuscular,intraperitoneal, intravenous, conjunctival and subcutaneous routes. Inbirds, the methods may further include choanal inoculation. As analternative to parenteral administration, the invention alsoencompasses, routes of mass administration for agricultural purposessuch as via drinking water or in a spray. It may be preferable tointroduce the chimeric influenza virus immunogenic formulation via thenatural route of infection of the wild-type virus. Alternatively, it maybe preferable to introduce the chimeric virus of the invention via thenatural route of infection of the agent from which the fusion protein isderived. The ability of chimeric virus to induce a vigorous secretoryand cellular immune response can be used advantageously. For example,infection of the respiratory tract by the chimeric viruses may induce astrong secretory immune response, for example in the urogenital system,with concomitant protection against a particular disease causing agent.In addition, in a preferred embodiment it may be desirable to introducethe pharmaceutical formulations of the invention into the lungs by anysuitable route. Pulmonary administration can also be employed, e.g., byuse of an inhaler or nebulizer, and formulation with an aerosolizingagent for use as a spray.

In certain embodiments, an immunogenic formulation of the invention doesnot result in complete protection from an infection (e.g., a viralinfection or infection by a non-viral infectious agent), but results ina lower titer or reduced number of the pathogen (e.g., a virus) comparedto an untreated subject. In certain embodiments, administration of theimmunogenic formulations of the invention results in a 0.5 fold, 1 fold,2 fold, 4 fold, 6 fold, 8 fold, 10 fold, 15 fold, 20 fold, 25 fold, 50fold, 75 fold, 100 fold, 125 fold, 150 fold, 175 fold, 200 fold, 300fold, 400 fold, 500 fold, 750 fold, or 1,000 fold or greater reductionin titer of the pathogen relative to an untreated subject. Benefits of areduction in the titer, number or total burden of pathogen include, butare not limited to, less severity of symptoms of the infection and areduction in the length of the disease or condition associated with theinfection.

In certain embodiments, an immunogenic formulation of the invention isused to protect against a disease (e.g., an infection) in naïvesubjects. In a specific embodiment, an immunogenic formulation of theinvention is used to protect against an infection by influenza virusand/or at least one other infectious agent which is not an influenzavirus and/or protect against a disease or symptom associated with theinfection in a naïve subject. In other embodiments, an immunogenicformulation of the invention is used to protect against infection by NDVand/or at least one other infectious agent and/or protect against adisease or symptom associated therewith in naïve subjects. Non-limitingexamples of such other infectious agents are papilloma virus, herpesvirus, retrovirus (e.g. HIV), hepatitis virus, rhinovirus, respiratorysynctial virus, NDV, cytomegalovirus, adenovirus, Clostridia sp.,Salmonella sp., Staphylococcus sp., Enterococcus sp., Vibrio sp., E.coli, Streptococcus equi, Mycoplasma pneumoniae, Klebsiella pneumoniaeand Pseudomonas aeruginosa, and Dermatophilus congolensis, or aprotozoan such as amobea, malarial parasite or Trypanosoma cruzi.

The prophylactic and/or therapeutic effect of the immunogenicformulations of the invention are based, in part, upon achieving orinducing an immune response (e.g., a hummoral immune response). In oneaspect, the immunogenic formulations induce a detectable serum titer ofan antibody against antigens of the chimeric virus in either the subjector an animal model thereof (e.g. mouse, rat or canine model). The serumtiter of an antibody can be determined using techniques known to one ofskill in the art, e.g., immunoassays such as ELISAs. In one embodiment,the antibodies specifically bind to an antigen of the backbone of thechimeric virus. In other embodiments, the antibodies specifically bindto an antigen of the at least one fusion protein, i.e., an antigen ofthe ectodomain of the introduced protein associated with an infectiousagent or disease. In a specific embodiment, the antibodies generated byadministering an immunogenic formulation of the invention areneutralizing antibodies.

In one embodiment, administration of a chimeric virus of the inventionto a subject or animal model thereof results in a serum titer of about 1μg/ml, about 2 μg/ml, about 5 μg/ml, about 6 μg/ml, about 10 μg/ml,about 15 μg/ml, about 20 μg/ml, about 25 μg/ml, about 50 mg/ml, about 75mg/ml, about 100 mg/ml, about 125 mg/ml, about 150 mg/ml, about 175mg/ml, about 200 mg/ml, about 225 mg/ml, about 250 mg/ml, about 275mg/ml, or about 300 mg/ml or more of an antibody that specifically bindsto an antigen of the backbone of the chimeric virus. In otherembodiments, administration of a chimeric virus of the invention to asubject or animal model thereof results in a serum titer of about 1μg/ml, about 2 μg/ml, about 5 μg/ml, about 6 μg/ml, about 10 μg/ml,about 15 μg/ml, about 20 μg/ml, about 25 μg/ml, about 50 mg/ml, about 75mg/ml, about 100 mg/ml, about 125 mg/ml, about 150 mg/ml, about 175mg/ml, about 200 mg/ml, about 225 mg/ml, about 250 mg/ml, about 275mg/ml, or about 300 mg/ml or more of an antibody that specifically bindsto an antigen of fusion protein, i.e., an antigen of the ectodomain ofthe introduced protein associated with an infectious agent or disease.Preferably a serum titer of about 1 μg/ml, about 2 μg/ml, about 5 μg/ml,about 6 μg/ml, about 10 μg/ml, about 15 μg/ml, about 20 μg/ml, about 25μg/ml, about 50 mg/ml, about 100 mg/ml, about 150 mg/ml or about 300mg/ml or more of such antibodies is achieved approximately 20 days(preferably 25, 30, 35 or 40 days) after administration of a first doseof an immunogenic formulation of the invention and withoutadministration of any other doses the formulation. The immune responsemay be determined in the subject or in a animal model, which response isthen correlated or extrapolated to a predicted response in the subject,e.g., a human.

In one embodiment, the present invention provides methods for preventingat least one disease (e.g., an influenza infection and/or infections byanother infectious agent which is not influenza) in a subject, themethods comprising administering to said subject a first dose of aneffective amount of an immunogenic formulation comprising a chimericinfluenza virus of the invention, which chimeric virus comprises afusion protein of a heterologous sequence (e.g. a disease antigen),wherein the effective amount is the amount that results in a serum titerof about 10 μg/ml, 20 μg/ml, 30 μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70μg/ml, 80 μg/ml, 100 μg/ml or greater of antibodies thatimmunospecifically bind to an antigen or epitope of the backbone of thechimeric virus 2 days, 5 days, 10 days, 15 days, 20 days or, preferably,30 days after the first administration and prior to any subsequentadministration. In another embodiment, the present invention providesmethods for preventing at least one disease (e.g., an influenzainfection and/or infections by another infectious agent which is notinfluenza) in a subject, the methods comprising administering to saidsubject a first dose of an effective amount of an immunogenicformulation comprising a chimeric influenza virus of the invention,which chimeric virus comprises a fusion protein of a heterologoussequence (e.g. a disease antigen), wherein the effective amount is theamount that results in a serum titer of about 10 μg/ml, 20 μg/ml, 30μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml orgreater of antibodies that immunospecifically bind to an antigen of thefusion protein (i.e., an antigen of the ectodomain of the introducedprotein associated with a disease) at 2 days, 5 days, 10 days, 15 days,20 days or, preferably, 30 days after the first administration and priorto any subsequent administration. The immune response may be determinedin the subject or in a animal model, which response is then correlatedor extrapolated to a predicted response in the subject, e.g., a human.In one embodiment, the present invention provides methods for preventingan avian influenza infection and/or infections by another infectiousagent which is not avian influenza in an avian, the method comprisingadministering a first dose of an immunogenic formulation comprising achimeric avian influenza virus of the invention, which chimeric avianinfluenza virus comprises a fusion protein containing a heterologousprotein sequence, to said subject of an effective amount of the chimericavian virus of the invention, wherein the effective amount is the amountthat results in a serum titer of about 10 μg/ml, 20 μg/ml, 30 μg/ml, 40μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml or greater ofantibodies that immunospecifically bind to an antigen of the chimericvirus and/or antibodies that immunospecifically bind to an antigen ofthe fusion protein 2 days, 5 days, 10 days, 15 days, 20 days or,preferably, 30 days after the first administration and prior to anysubsequent administration. In some embodiments, the dose of the chimericinfluenza virus administered to the subject or animal model is 10²,5×10², 10³, 5×10³, 10⁴, 5×10⁴, 10⁵, 5×10⁵, 10⁶, 5×10⁶ 10⁷, 5×10⁷, 10⁸,5×10⁸, 1×10⁹, 5×10⁹, 1×10¹⁰, 5×10¹⁰, 1×10¹¹, 5×10¹¹ or 10¹² pfu.

In one embodiment, the present invention provides methods for treatingat least one disease (e.g., an influenza infection and/or infections byanother infectious agent which is not influenza) in a subject, themethods comprising administering to said subject a first dose of aneffective amount of an immunogenic formulation comprising a chimericinfluenza virus of the invention, which chimeric virus comprises afusion protein of a heterologous sequence (e.g. a disease antigen),wherein the effective amount is the amount that results in a serum titerof about 10 μg/ml, 20 μg/ml, 30 μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70μg/ml, 80 μg/ml, 100 μg/ml or greater of antibodies thatimmunospecifically bind to an antigen or epitope of the backbone of thechimeric virus 2 days, 5 days, 10 days, 15 days, 20 days or, preferably,30 days after the first administration and prior to any subsequentadministration. In another embodiment, the present invention providesmethods for treating at least one disease (e.g., an influenza infectionand/or infections by another infectious agent which is not influenza) ina subject, the methods comprising administering to said subject a firstdose of an effective amount of an immunogenic formulation comprising achimeric influenza virus of the invention, which chimeric viruscomprises a fusion protein of a heterologous sequence (e.g. a diseaseantigen), wherein the effective amount is the amount that results in aserum titer of about 10 μg/ml, 20 μg/ml, 30 μg/ml, 40 μg/ml, 50 μg/ml,60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml or greater of antibodies thatimmunospecifically bind to an antigen of the fusion protein (i.e., anantigen of the ectodomain of the introduced protein associated with adisease) at 2 days, 5 days, 10 days, 15 days, 20 days or, preferably, 30days after the first administration and prior to any subsequentadministration. The immune response may be determined in the subject orin a animal model, which response is then correlated or extrapolated toa predicted response in the subject, e.g., a human. In one embodiment,the present invention provides methods for treating an avian influenzainfection and/or infections by another infectious agent which is notavian influenza in an avian, the method comprising administering a firstdose of an immunogenic formulation comprising a chimeric avian influenzavirus of the invention, which chimeric avian influenza virus comprises afusion protein containing a heterologous protein sequence, to saidsubject of an effective amount of the chimeric avian virus of theinvention, wherein the effective amount is the amount that results in aserum titer of about 10 μg/ml, 20 μg/ml, 30 μg/ml, 40 μg/ml, 50 μg/ml,60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml or greater of antibodies thatimmunospecifically bind to an antigen of the chimeric virus and/orantibodies that immunospecifically bind to an antigen of the fusionprotein 2 days, 5 days, 10 days, 15 days, 20 days or, preferably, 30days after the first administration and prior to any subsequentadministration. In some embodiments, the dose of the chimeric influenzavirus administered to the subject or animal model is 10², 5×10², 10³,5×10³, 10⁴, 5×10⁴, 10⁵, 5×10⁵, 10⁶, 5×10⁶, 10⁷, 5×10⁷, 10⁸, 5×10⁸,1×10⁹, 5×10⁹, 1×10¹⁰, 5×10¹⁰, 1×10¹¹, 5×10¹¹ or 10¹² pfu.

In one embodiment, the present invention provides methods for managingand/or ameliorating at least one disease (e.g., an influenza infectionand/or infections by another infectious agent which is not influenza) ina subject, the methods comprising administering to said subject a firstdose of an effective amount of an immunogenic formulation comprising achimeric influenza virus of the invention, which chimeric viruscomprises a fusion protein of a heterologous sequence (e.g. a diseaseantigen), wherein the effective amount is the amount that results in aserum titer of about 10 μg/ml, 20 μg/ml, 30 μg/ml, 40 μg/ml, 50 μg/ml,60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml or greater of antibodies thatimmunospecifically bind to an antigen or epitope of the backbone of thechimeric virus 2 days, 5 days, 10 days, 15 days, 20 days or, preferably,30 days after the first administration and prior to any subsequentadministration. In another embodiment, the present invention providesmethods for managing and/or ameliorating at least one disease (e.g., aninfluenza infection and/or infections by another infectious agent whichis not influenza) in a subject, the methods comprising administering tosaid subject a first dose of an effective amount of an immunogenicformulation comprising a chimeric influenza virus of the invention,which chimeric virus comprises a fusion protein of a heterologoussequence (e.g. a disease antigen), wherein the effective amount is theamount that results in a serum titer of about 10 μg/ml, 20 μg/ml, 30μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml orgreater of antibodies that immunospecifically bind to an antigen of thefusion protein (i.e., an antigen of the ectodomain of the introducedprotein associated with a disease) at 2 days, 5 days, 10 days, 15 days,20 days or, preferably, 30 days after the first administration and priorto any subsequent administration. The immune response may be determinedin the subject or in a animal model, which response is then correlatedor extrapolated to a predicted response in the subject, e.g., a human.In one embodiment, the present invention provides methods for managingand/or ameliorating an avian influenza infection and/or infections byanother infectious agent which is not avian influenza in an avian, themethod comprising administering a first dose of an immunogenicformulation comprising a chimeric avian influenza virus of theinvention, which chimeric avian influenza virus comprises a fusionprotein containing a heterologous protein sequence, to said subject ofan effective amount of the chimeric avian virus of the invention,wherein the effective amount is the amount that results in a serum titerof about 10 μg/ml, 20 μg/ml, 30 μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70μg/ml, 80 μg/ml, 100 μg/ml or greater of antibodies thatimmunospecifically bind to an antigen of the chimeric virus and/orantibodies that immunospecifically bind to an antigen of the fusionprotein 2 days, 5 days, 10 days, 15 days, 20 days or, preferably, 30days after the first administration and prior to any subsequentadministration. In some embodiments, the dose of the chimeric influenzavirus administered to the subject or animal model is 10², 5×10², 10³,5×10³, 10⁴, 5×10⁴, 10⁵, 5×10⁵, 10⁶, 5×10⁶ 10⁷, 5×10⁷, 10⁸, 5×10⁸, 1×10⁹,5×10⁹, 1×10¹⁰, 5×10¹⁰, 1×10¹¹, 5×10¹¹ or 10¹² pfu.

In one embodiment, the present invention provides methods for preventingat least one disease (e.g., an NDV infection and/or infections byanother infectious agent which is not NDV) in a subject, the methodscomprising administering to said subject a first dose of an effectiveamount of an immunogenic formulation comprising a chimeric NDV of theinvention, which chimeric virus comprises a fusion protein of aheterologous sequence (e.g. a disease antigen), wherein the effectiveamount is the amount that results in a serum titer of about 10 μg/ml, 20μg/ml, 30 μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100μg/ml or greater of antibodies that immunospecifically bind to anantigen or epitope of the backbone of the chimeric virus 2 days, 5 days,10 days, 15 days, 20 days or, preferably, 30 days after the firstadministration and prior to any subsequent administration. In anotherembodiment, the present invention provides methods for preventing atleast one disease (e.g., an NDV infection and/or infections by anotherinfectious agent which is not NDV) in a subject, the methods comprisingadministering to said subject a first dose of an effective amount of animmunogenic formulation comprising a chimeric NDV of the invention,which chimeric virus comprises a fusion protein of a heterologoussequence (e.g. a disease antigen), wherein the effective amount is theamount that results in a serum titer of about 10 μg/ml, 20 μg/ml, 30μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml orgreater of antibodies that immunospecifically bind to an antigen of thefusion protein (i.e., an antigen of the ectodomain of the introducedprotein associated with a disease) at 2 days, 5 days, 10 days, 15 days,20 days or, preferably, 30 days after the first administration and priorto any subsequent administration. The immune response may be determinedin the subject or in a animal model, which response is then correlatedor extrapolated to a predicted response in the subject, e.g., a human.In one embodiment, the present invention provides methods for preventingan NDV infection and/or infections by another infectious agent which isnot NDV in an avian, the method comprising administering a first dose ofan immunogenic formulation comprising a chimeric NDV of the invention,which chimeric NDV comprises a fusion protein containing a heterologousprotein sequence, to said subject of an effective amount of the chimericvirus of the invention, wherein the effective amount is the amount thatresults in a serum titer of about 10 μg/ml, 20 μg/ml, 30 μg/ml, 40μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml or greater ofantibodies that immunospecifically bind to an antigen of the chimericvirus and/or antibodies that immunospecifically bind to an antigen ofthe fusion protein 2 days, 5 days, 10 days, 15 days, 20 days or,preferably, 30 days after the first administration and prior to anysubsequent administration. In some embodiments, the dose of the chimericinfluenza virus administered to the subject or animal model is 10²,5×10², 10³, 5×10³, 10⁴, 5×10⁴, 10⁵, 5×10⁵, 10⁶, 5×10⁶, 10⁷, 5×10⁷, 10⁸,5×10⁸, 1×10⁹, 5×10⁹, 1×10¹⁰, 5×10¹⁰, 1×10¹¹, 5×10¹¹ or 10¹² pfu.

In one embodiment, the present invention provides methods for treatingat least one disease (e.g., an NDV infection and/or infections byanother infectious agent which is not NDV) in a subject, the methodscomprising administering to said subject a first dose of an effectiveamount of an immunogenic formulation comprising a chimeric NDV of theinvention, which chimeric virus comprises a fusion protein of aheterologous sequence (e.g. a disease antigen), wherein the effectiveamount is the amount that results in a serum titer of about 10 μg/ml, 20μg/ml, 30 μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100μg/ml or greater of antibodies that immunospecifically bind to anantigen or epitope of the backbone of the chimeric virus 2 days, 5 days,10 days, 15 days, 20 days or, preferably, 30 days after the firstadministration and prior to any subsequent administration. In anotherembodiment, the present invention provides methods for treating at leastone disease (e.g., an NDV infection and/or infections by anotherinfectious agent which is not NDV) in a subject, the methods comprisingadministering to said subject a first dose of an effective amount of animmunogenic formulation comprising a chimeric NDV of the invention,which chimeric virus comprises a fusion protein of a heterologoussequence (e.g. a disease antigen), wherein the effective amount is theamount that results in a serum titer of about 10 μg/ml, 20 μg/ml, 30μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml orgreater of antibodies that immunospecifically bind to an antigen of thefusion protein (i.e., an antigen of the ectodomain of the introducedprotein associated with a disease) at 2 days, 5 days, 10 days, 15 days,20 days or, preferably, 30 days after the first administration and priorto any subsequent administration. The immune response may be determinedin the subject or in a animal model, which response is then correlatedor extrapolated to a predicted response in the subject, e.g., a human.In one embodiment, the present invention provides methods for treatingan NDV infection and/or infections by another infectious agent which isnot NDV in an avian, the method comprising administering a first dose ofan immunogenic formulation comprising a chimeric NDV of the invention,which chimeric NDV comprises a fusion protein containing a heterologousprotein sequence, to said subject of an effective amount of the chimericvirus of the invention, wherein the effective amount is the amount thatresults in a serum titer of about 10 μg/ml, 20 μg/ml, 30 μg/ml, 40μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml or greater ofantibodies that immunospecifically bind to an antigen of the chimericvirus and/or antibodies that immunospecifically bind to an antigen ofthe fusion protein 2 days, 5 days, 10 days, 15 days, 20 days or,preferably, 30 days after the first administration and prior to anysubsequent administration. In some embodiments, the dose of the chimericinfluenza virus administered to the subject or animal model is 10²,5×10², 10³, 5×10³, 10⁴, 5×10⁴, 10⁵, 5×10⁵, 10⁶, 5×10⁶, 10⁷, 5×10⁷, 10⁸,5×10⁸, 1×10⁹, 5×10⁹, 1×10¹⁰, 5×10¹⁰, 1×10¹¹, 5×10¹¹ or 10¹² pfu.

In one embodiment, the present invention provides methods for managingand/or ameliorating at least one disease (e.g., an NDV infection and/orinfections by another infectious agent which is not NDV) in a subject,the methods comprising administering to said subject a first dose of aneffective amount of an immunogenic formulation comprising a chimeric NDVof the invention, which chimeric virus comprises a fusion protein of aheterologous sequence (e.g. a disease antigen), wherein the effectiveamount is the amount that results in a serum titer of about 10 μg/ml, 20μg/ml, 30 μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100μg/ml or greater of antibodies that immunospecifically bind to anantigen or epitope of the backbone of the chimeric virus 2 days, 5 days,10 days, 15 days, 20 days or, preferably, 30 days after the firstadministration and prior to any subsequent administration. In anotherembodiment, the present invention provides methods for managing and/orameliorating at least one disease (e.g., an NDV infection and/orinfections by another infectious agent which is not NDV) in a subject,the methods comprising administering to said subject a first dose of aneffective amount of an immunogenic formulation comprising a chimeric NDVof the invention, which chimeric virus comprises a fusion protein of aheterologous sequence (e.g. a disease antigen), wherein the effectiveamount is the amount that results in a serum titer of about 10 μg/ml, 20μg/ml, 30 μg/ml, 40 μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100μg/ml or greater of antibodies that immunospecifically bind to anantigen of the fusion protein (i.e., an antigen of the ectodomain of theintroduced protein associated with a disease) at 2 days, 5 days, 10days, 15 days, 20 days or, preferably, 30 days after the firstadministration and prior to any subsequent administration. The immuneresponse may be determined in the subject or in a animal model, whichresponse is then correlated or extrapolated to a predicted response inthe subject, e.g., a human. In one embodiment, the present inventionprovides methods for managing and/or ameliorating an NDV infectionand/or infections by another infectious agent which is not NDV in anavian, the method comprising administering a first dose of animmunogenic formulation comprising a chimeric NDV of the invention,which chimeric NDV comprises a fusion protein containing a heterologousprotein sequence, to said subject of an effective amount of the chimericvirus of the invention, wherein the effective amount is the amount thatresults in a serum titer of about 10 μg/ml, 20 μg/ml, 30 μg/ml, 40μg/ml, 50 μg/ml, 60 μg/ml, 70 μg/ml, 80 μg/ml, 100 μg/ml or greater ofantibodies that immunospecifically bind to an antigen of the chimericvirus and/or antibodies that immunospecifically bind to an antigen ofthe fusion protein 2 days, 5 days, 10 days, 15 days, 20 days or,preferably, 30 days after the first administration and prior to anysubsequent administration. In some embodiments, the dose of the chimericinfluenza virus administered to the subject or animal model is 10²,5×10², 10³, 5×10³, 10⁴, 5×10⁴, 10⁵, 5×10⁵, 10⁶, 5×10⁶, 10⁷, 5×10⁷, 10⁸,5×10⁸, 1×10⁹, 5×10⁹, 1×10¹⁰, 5×10¹⁰, 1×1011, 5×10¹¹ or 10¹² pfu.

The present invention also provides methods for preventing, treatingand/or managing at least one disease, the methods comprisingadministering to said subject an effective amount of an immunogenicformulation comprising a chimeric influenza virus of the invention,wherein the effective amount is the amount that results in a reductionin mortality, reduction in hospitalization, reduction in the severity ofthe disease and/or reduction in the clinical symptoms of the diseaserelative to a subject not administered the immunogenic formulation ofthe invention. In certain embodiments the subject is a human. In someembodiments, the dose of the chimeric influenza virus administered tothe subject is 10², 5×10², 10³, 5×10³, 10⁴, 5×10⁴, 10⁵, 5×10⁵, 10⁶,5×10, 10⁷, 10⁸, 5×10⁷, 10⁸, 5×10, 1×10⁹, 5×10⁹, 1×10¹⁰, 5×10¹⁰, 1×10¹¹,5×10¹¹ or 10¹² pfu.

In another embodiment, the present invention provides methods forpreventing, treating and/or managing at least one disease (e.g., anavian influenza infection and/or infection by another infectious agentwhich is not avian influenza) in a subject (preferably avian), themethods comprising administering to said subject an effective amount ofa immunogenic formulation comprising a chimeric avian influenza virus ofthe invention, wherein the effective amount is the amount that resultsin a reduction in the titer or number of infectious agents, reduction inmortality, reduction in hospitalization, reduction in the severity ofinfection and/or reduction in the clinical symptoms of the infectionrelative to a subject not administered the immunogenic formulation ofthe invention. In some embodiments, the dose of the chimeric avianinfluenza virus administered to the subject is 10², 5×10², 10³, 5×10³,10⁴, 5×10⁴, 10⁵, 5×10⁵, 10⁶, 5×10⁶, 10⁷, 5×10⁷, 10⁸, 5×10⁸, 1×10⁹,5×10⁹, 1×10¹⁰, 5×10¹⁰, 1×10¹¹, 5×10¹¹ or 10¹² pfu. In certainembodiments, administration of the immunogenic formulation of theinvention results in a 10%, 20%, 30%, 40%, 50%, 60%, 70%, or 80% or morereduction in the replication of the infectious agent relative to asubject not administered the immunogenic formulation of the invention asdetermined at 2 days, 5 days, 10 days, 15 days, 20 days or, preferably,30 days after said administration by any method known in the art orexemplified herein (e.g., determination of viral titer). In otherembodiments, administration of an immunogenic formulation of theinvention results in a 1, 2, 3, 4, 5, 10, 15, 20, 25, 50, 75, or 100fold reduction in the replication of the infectious agent or the burdenof infectious agent relative to a subject not administered animmunogenic formulation of the invention as determined at 2 days, 5days, 10 days, 15 days, 20 days or, preferably, 30 days after saidadministration by any method known in the art or exemplified herein(e.g., determination of viral titer or bacterial load and/orconcentration).

In another embodiment, the present invention provides methods forpreventing, treating and/or ameliorating at least one disease (e.g., anNDV infection and/or infection by another infectious agent which is notNDV) in a subject (e.g., an avian), the methods comprising administeringto said subject an effective amount of an immunogenic formulationcomprising a chimeric NDV virus of the invention, wherein the effectiveamount is the amount that results in a reduction in the titer or numberof infectious agents, reduction in mortality, reduction inhospitalization, reduction in the severity of infection and/or reductionin the clinical symptoms of the infection relative to a subject notadministered the immunogenic formulation of the invention. In someembodiments, the dose of the chimeric NDV virus administered to thesubject is 10², 5×10², 10³, 5×10³, 10⁴, 5×10⁴, 10⁵, 5×10⁵, 10⁶, 5×10⁶,10⁷, 5×10⁷, 10⁸, 5×10⁸, 1×10⁹, 5×10⁹, 1×10¹⁰, 5×10¹⁰, 1×10¹¹, 5×10¹¹ or10¹² pfu. In certain embodiments, administration of the immunogenicformulation of the invention results in a 10%, 20%, 30%, 40%, 50%, 60%,70%, or 80% or more reduction in the replication of the infectious agentrelative to a subject not administered the immunogenic formulation ofthe invention as determined at 2 days, 5 days, 10 days, 15 days, 20 daysor, preferably, 30 days after said administration by any method known inthe art or exemplified herein (e.g., determination of viral titer). Inother embodiments, administration of the immunogenic formulation of theinvention results in a 1, 2, 3, 4, 5, 10, 15, 20, 25, 50, 75, or 100fold reduction in the replication of the infectious agent or the burdenof infectious agent relative to a subject not administered theimmunogenic formulation of the invention as determined at 2 days, 5days, 10 days, 15 days, 20 days or, preferably, 30 days after saidadministration by any method known in the art or exemplified herein(e.g., determination of viral titer).

The amount of the immunogenic formulation of the invention which will beeffective in the treatment, prevention an/or amelioration of aparticular disease (e.g. viral infection) will depend on the nature ofthe disease, and can be determined by standard clinical techniques. Inaddition, in vitro assays may optionally be employed to help identifyoptimal dosage ranges. The precise dose to be employed in theformulation will also depend on the route of administration, and theseriousness of the infection or disorder, and should be decidedaccording to the judgment of the practitioner and each subject'scircumstances. However, suitable dosage ranges for administration aregenerally about 10², 5×10², 10³, 5×10³, 10⁴, 5×10⁴ 10⁵ 5×10⁵ 10⁶ 5×10⁶10⁷ 5×10⁷ 10⁸ 5×10⁸ 1×10⁹ 5×10⁹ 1×10¹⁰ 5×10¹⁰ 1×10¹¹, 5×10¹¹ or 10¹²pfu, and most preferably about 10⁴ to about 10¹², and can beadministered to a subject once, twice, three or more times withintervals as often as needed. Effective doses may be extrapolated fromdose response curves derived from in vitro or animal model test systems.

In various embodiments, the immunogenic formulations of the invention orantibodies generated by the chimeric viruses of the invention areadministered to a subject in combination with one or more othertherapies (e.g. antiviral or immunomodulatory therapies) for theprevention of at least one disease (e.g. an influenza infection and/orinfection by another infectious agent which is not influenza virus). Inother embodiments, the immunogenic formulations of the invention orantibodies generated by the chimeric viruses of the invention areadministered to a subject in combination with one or more othertherapies (e.g. antiviral or immunomodulatory therapies) for thetreatment of at least one disease (e.g. an influenza infection and/orinfection by another infectious agent which is not influenza virus). Inyet other embodiments, the immunogenic formulations of the invention orantibodies generated by the chimeric viruses of the invention areadministered to a subject in combination with one or more othertherapies (e.g. antiviral or immunomodulatory therapies) for themanagement and/or amelioration of at least one disease (e.g. aninfluenza infection and/or infection by another infectious agent whichis not influenza virus). In a specific embodiment, the immunogenicformulations of the invention or antibodies generated by the chimericviruses of the invention are administered to a subject in combinationwith one or more other therapies (e.g. antiviral or immunomodulatorytherapies) for the prevention of an avian influenza infection and/orinfection by another infectious agent which is not avian influenzavirus. In another specific embodiment, the immunogenic formulations ofthe invention or antibodies generated by the chimeric viruses of theinvention are administered to a subject in combination with one or moreother therapies (e.g. antiviral or immunomodulatory therapies) for thetreatment of an avian influenza infection and/or infection by anotherinfectious agent which is not avian influenza virus. In yet otherembodiments, the immunogenic formulations of the invention or antibodiesgenerated by the chimeric viruses of the invention are administered to asubject in combination with one or more other therapies (e.g. antiviralor immunomodulatory therapies) for the prevention of an NDV infectionand/or infection by another infectious agent which is not NDV. In stillother embodiments, the immunogenic formulations of the invention orantibodies generated by the chimeric viruses of the invention areadministered to a subject in combination with one or more othertherapies (e.g. antiviral or immunomodulatory therapies) for thetreatment of an NDV infection and/or infection by another infectiousagent which is not NDV. In certain embodiments, the therapies (e.g.,prophylactic or therapeutic agents) are administered less than 5 minutesapart, less than 30 minutes apart, 1 hour apart, at about 1 hour apart,at about 1 to about 2 hours apart, at about 2 hours to about 3 hoursapart, at about 3 hours to about 4 hours apart, at about 4 hours toabout 5 hours apart, at about 5 hours to about 6 hours apart, at about 6hours to about 7 hours apart, at about 7 hours to about 8 hours apart,at about 8 hours to about 9 hours apart, at about 9 hours to about 10hours apart, at about 10 hours to about 11 hours apart, at about 11hours to about 12 hours apart, at about 12 hours to 18 hours apart, 18hours to 24 hours apart, 24 hours to 36 hours apart, 36 hours to 48hours apart, 48 hours to 52 hours apart, 52 hours to 60 hours apart, 60hours to 72 hours apart, 72 hours to 84 hours apart, 84 hours to 96hours apart, or 96 hours to 120 hours part. In preferred embodiments,two or more therapies are administered within the same patent visit.

Any anti-viral agent well-known to one of skill in the art can be usedin the formulations (e.g., vaccine formulations) and the methods of theinvention. Non-limiting examples of anti-viral agents include proteins,polypeptides, peptides, fusion proteins antibodies, nucleic acidmolecules, organic molecules, inorganic molecules, and small moleculesthat inhibit and/or reduce the attachment of a virus to its receptor,the internalization of a virus into a cell, the replication of a virus,or release of virus from a cell. In particular, anti-viral agentsinclude, but are not limited to, nucleoside analogs (e.g., zidovudine,acyclovir, gangcyclovir, vidarabine, idoxuridine, trifluridine, andribavirin), foscarnet, amantadine, rimantadine, saquinavir, indinavir,ritonavir, alpha-interferons and other interferons, and AZT.

In specific embodiments, the anti-viral agent is an immunomodulatoryagent that is immunospecific for a viral antigen. As used herein, theterm “viral antigen” includes, but is not limited to, any viral peptide,polypeptide and protein (e.g., HIV gp120, HIV nef, RSV F glycoprotein,RSV G glycoprotein, influenza virus neuraminidase, influenza virushemagglutinin, HTLV tax, herpes simplex virus glycoprotein (e.g., gB,gC, gD, and gE) and hepatitis B surface antigen) that is capable ofeliciting an immune response. Antibodies useful in this invention fortreatment of a viral infectious disease include, but are not limited to,antibodies against antigens of pathogenic viruses, including as examplesand not by limitation: adenovirdiae (e.g., mastadenovirus andaviadenovirus), herpesviridae (e.g., herpes simplex virus 1, herpessimplex virus 2, herpes simplex virus 5, and herpes simplex virus 6),leviviridae (e.g., levivirus, enterobacteria phase MS2, allolevirus),poxviridae (e.g., chordopoxvirinae, parapoxvirus, avipoxvirus,capripoxvirus, leporiipoxvirus, suipoxvirus, molluscipoxvirus, andentomopoxvirinae), papovaviridae (e.g., polyomavirus andpapillomavirus), paramyxoviridae (e.g., paramyxovirus, parainfluenzavirus 1, mobillivirus (e.g., measles virus), rubulavirus (e.g., mumpsvirus), pneumonovirinae (e.g., pneumovirus, human respiratory synctialvirus), and metapneumovirus (e.g., avian pneumovirus and humanmetapneumovirus)), picornaviridae (e.g., enterovirus, rhinovirus,hepatovirus (e.g., human hepatits A virus), cardiovirus, andapthovirus), reoviridae (e.g., orthoreovirus, orbivirus, rotavirus,cypovirus, fijivirus, phytoreovirus, and oryzavirus), retroviridae(e.g., mammalian type B retroviruses, mammalian type C retroviruses,avian type C retroviruses, type D retrovirus group, BLV-HTLVretroviruses, lentivirus (e.g. human immunodeficiency virus 1 and humanimmunodeficiency virus 2), spumavirus), flaviviridae (e.g., hepatitis Cvirus, dengue virus, West nile virus), hepadnaviridae (e.g., hepatitis Bvirus), togaviridae (e.g., alphavirus (e.g., sindbis virus) andrubivirus (e.g., rubella virus)), rhabdoviridae (e.g., vesiculovirus,lyssavirus, ephemerovirus, cytorhabdovirus, and necleorhabdovirus),arenaviridae (e.g., arenavirus, lymphocytic choriomeningitis virus, Ippyvirus, and lassa virus), and coronaviridae (e.g., coronavirus andtorovirus).

Anti-bacterial agents and therapies well known to one of skill in theart for the prevention, treatment, management, or amelioration ofbacterial infections can be used in the compositions (e.g., immunogenicformulations) and methods of the invention. Non-limiting examples ofanti-bacterial agents include proteins, polypeptides, peptides, fusionproteins, antibodies, nucleic acid molecules, organic molecules,inorganic molecules, and small molecules that inhibit or reduce abacterial infection, inhibit or reduce the replication of bacteria, orinhibit or reduce the spread of bacteria to other subjects. Inparticular, examples of anti-bacterial agents include, but are notlimited to, penicillin, cephalosporin, imipenem, axtreonam, vancomycin,cycloserine, bacitracin, chloramphenicol, erythromycin, clindamycin,tetracycline, streptomycin, tobramycin, gentamicin, amikacin, kanamycin,neomycin, spectinomycin, trimethoprim, norfloxacin, rifampin, polymyxin,amphotericin B, nystatin, ketocanazole, isoniazid, metronidazole, andpentamidine. Anti-bacterial therapies and their dosages, routes ofadministration and recommended usage are known in the art and have beendescribed in such literature as the Physician's Desk Reference (56^(th)ed., 2002). Additional information on respiratory infections andanti-bacterial therapies is available in Cecil Textbook of Medicine(18th ed., 1988).

Anti-fungal agents and therapies well known to one of skill in the artfor prevention, management, treatment, and/or amelioration of a fungalinfection or one or more symptoms thereof (e.g., a fungal respiratoryinfection) can be used in the compositions (e.g., immunogenicformulations) and methods of the invention. Non-limiting examples ofanti-fungal agents include proteins, polypeptides, peptides, fusionproteins, antibodies, nucleic acid molecules, organic molecules,inorganic molecules, and small molecules that inhibit and/or reducefungal infection, inhibit and/or reduce the replication of fungi, orinhibit and/or reduce the spread of fungi to other subjects. Specificexamples of anti-fungal agents include, but are not limited to, azoledrugs (e.g., miconazole, ketoconazole (NIZORAL®), caspofungin acetate(CANCIDAS®), imidazole, triazoles (e.g., fluconazole (DIFLUCAN®)), anditraconazole (SPORANOX®)), polyene (e.g., nystatin, amphotericin B(FUNGIZONE®), amphotericin B lipid complex (“ABLC”)(ABELCET®),amphotericin B colloidal dispersion (“ABCD”)(AMPHOTEC®), liposomalamphotericin B (AMBISONE®)), potassium iodide (KI), pyrimidine (e.g.,flucytosine (ANCOBON®)), and voriconazole (VFEND®). Anti-fungaltherapies and their dosages, routes of administration, and recommendedusage are known in the art and have been described in such literature asDodds et al., 2000 Pharmacotherapy 20(11) 1335-1355, the Physician'sDesk Reference (57th ed., 2003) and the Merk Manual of Diagnosis andTherapy (17th ed., 1999).

In certain embodiments, an immunogenic formulation of the invention isadministered to a subject as a single dose followed by a second dose 3to 6 weeks later. In accordance with these embodiments, boosterinoculations may be administered to the subject at 6 to 12 monthintervals following the second inoculation. In one embodiment, thesubject is a mammal. In another embodiment, the subject is a bird. Inyet another embodiment the subject is a human. In a more preferredembodiment, the subject is a chicken at risk for contracting either NDVor avian influenza virus infection.

In certain embodiments, the administration of the same immunogenicformulations of the invention may be repeated and the administrationsmay be separated by at least 1 day, 2 days, 3 days, 5 days, 10 days, 15days, 30 days, 45 days, 2 months, 75 days, 3 months, or at least 6months.

5.6 Biological Assays

5.6.1 In Vitro Assays

Growth of the chimeric viruses of the present invention can be assessedby any method known in the art or described herein (e.g in cell culture(e.g., cultures of chicken embryonic kidney cells or cultures of chickenembryonic fibroblasts(CEF)). Growth of the attenuated chimeric virusesof the invention can be assessed in IFN-competent and IFN-deficientcells. In a specific embodiment, CEF cells are infected at a MOI of0.0005 and 0.001, 0.001 and 0.01, 0.01 and 0.1, 0.1 and 1, or 1 and 10,or a MOI of 0.0005, 0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 5 or 10 andincubated with serum free media supplemented with 5% allantoic fluid.Viral titers are determined in the supernatant by HA plagued in CEFcells as described below. Other cells in which viral titers can beassessed include, but are not limited to, EFK-2 cells, Vero cells,primary human umbilical vein endothelial cells (HUVEC), H292 humanepithelial cell line and HeLa cells.

Incorporation of the fusion protein into the virion of the chimericviruses of the present invention can be assessed by any method known inthe art or described herein (e.g. in cell culture, animal model or viralculture in embryonated eggs). For example, viral particles from cellculture of the allantoic fluid of embryonated eggs can be purified bycentrifugation through a sucrose cushion and subsequently analyzed forfusion protein expression by Western blotting using methods well knownin the art.

Viral assays include those that measure altered viral replication (asdetermined, e.g., by plaque formation) or the production of viralproteins (as determined, e.g., by western blot analysis) or viral RNAs(as determined, e.g., by RT-PCR or northern blot analysis) in culturedcells in vitro using methods which are well known in the art.

Antibodies generated by the chimeric viruses of the present invention orfragments thereof may be characterized in a variety of ways well-knownto one of skill in the art (e.g. ELISA, Surface Plasmon resonancedisplay (BIAcore), Western blot, immunofluorescence, immunostainingand/or microneutralization assays). In particular, antibodies generatedby the chimeric viruses of the present invention or fragments thereofmay be assayed for the ability to immunospecifically bind to an antigenof the chimeric backbone virus or an antigen or epitope of the fusionprotein. Such an assay may be performed in solution (e.g., Houghten,1992, Bio/Techniques 13:412-421), on beads (Lam, 1991, Nature354:82-84), on chips (Fodor, 1993, Nature 364:555-556), on bacteria(U.S. Pat. No. 5,223,409), on spores (U.S. Pat. Nos. 5,571,698;5,403,484; and 5,223,409), on plasmids (Cull et al., 1992, Proc. Natl.Acad. Sci. USA 89:1865-1869) or on phage (Scott and Smith, 1990, Science249:386-390; Cwirla et al., 1990, Proc. Natl. Acad. Sci. USA87:6378-6382; and Felici, 1991, J. Mol. Biol. 222:301-310) (each ofthese references is incorporated herein in its entirety by reference).Antibodies generated by the chimeric viruses of the present invention orfragments thereof that have been identified to immunospecifically bindto an antigen of the chimeric backbone virus or an antigen or epitope ofthe fusion protein can then be assayed for their specificity to saidantigen.

The antibodies generated by the chimeric viruses of the presentinvention or fragments thereof may be assayed for immunospecific bindingto an antigen of the chimeric virus of the invention (e.g., an antigenor epitope of the chimeric virus backbone or an antigen or epitope ofthe fusion protein (e.g., an antigen associated with a disease)) andcross-reactivity with other antigens by any method known in the art.Immunoassays which can be used to analyze immunospecific binding andcross-reactivity include, but are not limited to, competitive andnon-competitive assay systems using techniques such as western blots,radioimmunoassays, ELISA (enzyme linked immunosorbent assay), “sandwich”immunoassays, immunoprecipitation assays, precipitin reactions, geldiffusion precipitin reactions, immunodiffusion assays, agglutinationassays, complement-fixation assays, immunoradiometric assays,fluorescent immunoassays, protein A immunoassays, to name but a few.Such assays are routine and well known in the art (see, e.g., Ausubel etal., eds., 1994, Current Protocols in Molecular Biology, Vol. 1, JohnWiley & Sons, Inc., New York, which is incorporated by reference hereinin its entirety). Exemplary immunoassays are described briefly below(but are not intended by way of limitation).

Immunoprecipitation protocols generally comprise lysing a population ofcells in a lysis buffer such as RIPA buffer (1% NP-40 or Triton X-100,1% sodium deoxycholate, 0.1% SDS, 0.15 M NaCl, 0.01 M sodium phosphateat pH 7.2, 1% Trasylol) supplemented with protein phosphatase and/orprotease inhibitors (e.g., EDTA, PMSF, aprotinin, sodium vanadate),adding the antibody of interest to the cell lysate, incubating for aperiod of time (e.g., 1 to 4 hours) at 40° C., adding protein A and/orprotein G sepharose beads to the cell lysate, incubating for about anhour or more at 40° C., washing the beads in lysis buffer andresuspending the beads in SDS/sample buffer. The ability of the antibodyof interest to immunoprecipitate a particular antigen can be assessedby, e.g., western blot analysis. One of skill in the art would beknowledgeable as to the parameters that can be modified to increase thebinding of the antibody to an antigen and decrease the background (e.g.,pre-clearing the cell lysate with sepharose beads). For furtherdiscussion regarding immunoprecipitation protocols see, e.g., Ausubel etal., eds, 1994, Current Protocols in Molecular Biology, Vol. 1, JohnWiley & Sons, Inc., New York at 10.16.1.

Western blot analysis generally comprises preparing protein samples,electrophoresis of the protein samples in a polyacrylamide gel (e.g.,8%-20% SDS-PAGE depending on the molecular weight of the antigen),transferring the protein sample from the polyacrylamide gel to amembrane such as nitrocellulose, PVDF or nylon, incubating the membranein blocking solution (e.g., PBS with 3% BSA or non-fat milk), washingthe membrane in washing buffer (e.g., PBS-Tween 20), incubating themembrane with primary antibody (the antibody of interest) diluted inblocking buffer, washing the membrane in washing buffer, incubating themembrane with a secondary antibody (which recognizes the primaryantibody, e.g., an anti-human antibody) conjugated to an enzymaticsubstrate (e.g., horseradish peroxidase or alkaline phosphatase) orradioactive molecule (e.g., ³²P or ¹²⁵I) diluted in blocking buffer,washing the membrane in wash buffer, and detecting the presence of theantigen. One of skill in the art would be knowledgeable as to theparameters that can be modified to increase the signal detected and toreduce the background noise. For further discussion regarding westernblot protocols see, e.g., Ausubel et al, eds, 1994, Current Protocols inMolecular Biology, Vol. 1, John Wiley & Sons, Inc., New York at 10.8.1.

ELISAs comprise preparing antigen, coating the well of a 96 wellmicrotiter plate with the antigen, adding the antibody of interestconjugated to a detectable compound such as an enzymatic substrate(e.g., horseradish peroxidase or alkaline phosphatase) to the well andincubating for a period of time, and detecting the presence of theantigen. In ELISAs the antibody of interest does not have to beconjugated to a detectable compound; instead, a second antibody (whichrecognizes the antibody of interest) conjugated to a detectable compoundmay be added to the well. Further, instead of coating the well with theantigen, the antibody may be coated to the well. In this case, a secondantibody conjugated to a detectable compound may be added following theaddition of the antigen of interest to the coated well. One of skill inthe art would be knowledgeable as to the parameters that can be modifiedto increase the signal detected as well as other variations of ELISAsknown in the art. In a preferred embodiment, an ELISA may be performedby coating a high binding 96-well microtiter plate (Costar) with 2 μg/mlof rhu-IL-9 in PBS overnight. Following three washes with PBS, the plateis incubated with three-fold serial dilutions of Fab at 25° C. for 1hour. Following another three washes of PBS, 1 μg/ml anti-humankappa-alkaline phosphatase-conjugate is added and the plate is incubatedfor 1 hour at 25° C. Following three washes with PBST, the alkalinephosphatase activity is determined in 50 μl/AMP/PPMP substrate. Thereactions are stopped and the absorbance at 560 nm is determined with aVMAX microplate reader. For further discussion regarding ELISAs see,e.g., Ausubel et al, eds, 1994, Current Protocols in Molecular Biology,Vol. 1, John Wiley & Sons, Inc., New York at 11.2.1.

The binding affinity of an antibody to an antigen and the off-rate of anantibody-antigen interaction can be determined by competitive bindingassays. One example of a competitive binding assay is a radioimmunoassaycomprising the incubation of labeled antigen (e.g., ³H or ¹²⁵I) with theantibody of interest in the presence of increasing amounts of unlabeledantigen, and the detection of the antibody bound to the labeled antigen.The affinity of the antibody of the present invention or a fragmentthereof for an IL-9 polypeptide and the binding off-rates can bedetermined from the data by scatchard plot analysis. Competition with asecond antibody can also be determined using radioimmunoassays. In thiscase, an IL-9 polypeptide is incubated with an antibody of the presentinvention conjugated to a labeled compound (e.g., ³H or ¹²⁵I) in thepresence of increasing amounts of an unlabeled second antibody.

In a preferred embodiment, BIAcore kinetic analysis is used to determinethe binding on and off rates of antibodies of the invention to anantigen of the chimeric virus of the invention (e.g., an antigen orepitope of the chimeric virus backbone or an antigen or epitope of thefusion protein (e.g., an antigen associated with a disease)). BIAcorekinetic analysis comprises analyzing the binding and dissociation ofpolypeptide comprising the antigen of interes from chips withimmobilized antibodies generated by the chimeric viruses of theinvention on their surface. A typical BIAcore kinetic study involves theinjection of 250 μL of an antibody reagent (mAb, Fab) at varyingconcentration in HBS buffer containing 0.005% Tween-20 over a sensorchip surface, onto which has been immobilized the antigen. The flow rateis maintained constant at 75 μL/min. Dissociation data is collected for15 min. or longer as necessary. Following each injection/dissociationcycle, the bound mAb is removed from the antigen surface using brief, 1min. pulses of dilute acid, typically 10-100 mM HCl, though otherregenerates are employed as the circumstances warrant. Morespecifically, for measurement of the rates of association, k_(on), anddissociation, k_(off), the polypeptide comprising the antigen isdirectly immobilized onto the sensor chip surface through the use ofstandard amine coupling chemistries, namely the EDC/NHS method(EDC=N-diethylaminopropyl)-carbodiimide). Briefly, a 5-100 nM solutionof the polypeptide comprising the antigen in 10 mM NaOAc, pH4 or pH5 isprepared and passed over the EDC/NHS-activated surface untilapproximately 30-50 RU's worth of antigen are immobilized. Followingthis, the unreacted active esters are “capped” off with an injection of1M Et-NH2. A blank surface, containing no antigen, is prepared underidentical immobilization conditions for reference purposes. Once anappropriate surface has been prepared, a suitable dilution series ofeach one of the antibody reagents is prepared in HBS/Tween-20, andpassed over both the antigen and reference cell surfaces, which areconnected in series. The range of antibody concentrations that areprepared varies, depending on what the equilibrium binding constant,K_(D), is estimated to be. As described above, the bound antibody isremoved after each injection/dissociation cycle using an appropriateregenerate.

The antibodies generated by the chimeric viruses of the invention orfragments thereof can also be assayed for their ability to inhibit thebinding of an antigen of the chimeric virus of the invention (e.g., anantigen or epitope of the chimeric virus backbone or an antigen orepitope of the fusion protein (e.g., an antigen associated with adisease)) to a host cell receptor using techniques known to those ofskill in the art. For example, cells expressing receptors known to bindsaid antigens can be contacted with antigen in the presence or absenceof an antibody generated by the chimeric viruses of the invention orfragment thereof and the ability of the antibody or fragment thereof toinhibit the antigen's binding can measured by, for example, flowcytometry or a scintillation assay. The antigen or the antibody orantibody fragment can be labeled with a detectable compound such as aradioactive label (e.g., 32P, 35S, and 125I) or a fluorescent label(e.g., fluorescein isothiocyanate, rhodamine, phycoerythrin,phycocyanin, allophycocyanin, o-phthaldehyde and fluorescamine) toenable detection of an interaction between the antigen and a cellreceptor. Alternatively, the ability of antibodies generated by thechimeric viruses of the invention or fragments thereof to inhibit anantigen of the chimeric virus of the invention (e.g., an antigen orepitope of the chimeric virus backbone or an antigen or epitope of thefusion protein (e.g., an antigen associated with a disease)) frombinding to a receptor can be determined in cell-free assays. Forexample, a polypeptide comprising the antigen can be contacted with anantibody or fragment thereof and the ability of the antibody or antibodyfragment to inhibit the polypeptide from binding to a cell receptor canbe determined. Preferably, the antibody or the antibody fragment isimmobilized on a solid support and the polypeptide is labeled with adetectable compound. Alternatively, a polypeptide comprising the antigenis immobilized on a solid support and the antibody or fragment thereofis labeled with a detectable compound.

5.6.2 In Vivo Assays

The virulence of the chimeric viruses of the present invention can beassessed in a subject, in particular avians, or in an animal modelthereof. In one example, the ability to induce lung lesions and causeinfection in an animal model of virus infection is compared to wild-typevirus and mock virus. Lung lesions can be assessed as a percentage oflung lobes that are healthy by visual inspection. Animals are euthanized5 days p.i. by intravenous administration of pentobarbital, and theirlungs are removed in toto. The percentage of the surface of eachpulmonary lobe that is affected by macroscopic lesions is estimatedvisually. The percentages are averaged to obtain a mean value for the 7pulmonary lobes of each animal. In other assays, nasal swabs can betested to determine virus burden or titer. Nasal swabs can be takenduring necropsy to determine viral burden post-infection.

For quantitation of virus in tissue samples, tissue samples arehomogenized in phosphate-buffered saline (PBS), and dilutions ofclarified homogenates adsorbed for 1 h at 37° C. onto monolayers ofcells (e.g., CEF or MDCK cells). Infected monolayers are then overlaidwith a solution of minimal essential medium containing 0.1% bovine serumalbumin (BSA), 0.01% DEAE-dextran, 0.1% NaHCO₃, and 1% agar. Plates areincubated 2 to 3 days until plaques could be visualized. Tissue cultureinfectious dose (TCID) assays to titrate virus from PR8-infected samplesare carried out as follows. Confluent monolayers of cells (e.g., CEF orMDCK cells) in 96-well plates are incubated with log dilutions ofclarified tissue homogenates in media. Two to three days afterinoculation, 0.05-ml aliquots from each well are assessed for viralgrowth by hemagglutination assay (HA assay).

In yet other assays, histopathologic evaluations are performed afterinfection. Nasal turbinates and trachea may be examined for epithelialchanges and subepithelial inflammation. The lungs may be examined forbronchiolar epithelial changes and peribronchiolar inflammation inlarge, medium, and small or terminal bronchioles. The alveoli are alsoevaluated for inflammatory changes. The medium bronchioles are graded ona scale of 0 to 3+ as follows: 0 (normal: lined by medium to tallcolumnar epithelial cells with ciliated apical borders and basalpseudostratified nuclei; minimal inflammation); 1+(epithelial layercolumnar and even in outline with only slightly increased proliferation;cilia still visible on many cells); 2+(prominent changes in theepithelial layer ranging from attenuation to marked proliferation; cellsdisorganized and layer outline irregular at the luminal border);3+(epithelial layer markedly disrupted and disorganized with necroticcells visible in the lumen; some bronchioles attenuated and others inmarked reactive proliferation).

The trachea is graded on a scale of 0 to 2.5+ as follows: 0 (normal:Lined by medium to tall columnar epithelial cells with ciliated apicalborder, nuclei basal and pseudostratified. Cytoplasm evident betweenapical border and nucleus. Occasional small focus with squamous cells);1+(focal squamous metaplasia of the epithelial layer); 2+(diffusesquamous metaplasia of much of the epithelial layer, cilia may beevident focally); 2.5+(diffuse squamous metaplasia with very few ciliaevident).

Virus immunohistochemistry is performed using a viral-specificmonoclonal antibody (e.g. NP-, N- or HN-sepcific monoclonal antibodies).Staining is graded 0 to 3+ as follows: 0 (no infected cells); 0.5+(fewinfected cells); 1+(few infected cells, as widely separated individualcells); 1.5+(few infected cells, as widely separated singles and insmall clusters); 2+(moderate numbers of infected cells, usuallyaffecting clusters of adjacent cells in portions of the epithelial layerlining bronchioles, or in small sublobular foci in alveoli); 3+(numerousinfected cells, affecting most of the epithelial layer in bronchioles,or widespread in large sublobular foci in alveoli).

5.6.3 Determining Viral Titer

Viral titer is determined by inoculating serial dilutions of chimericvirus into cell cultures (e.g., CEF or MDCK), chick embryos, or liveanimals (e.g., avians). After incubation of the virus for a specifiedtime, the virus is isolated using standard methods.

The HA assay may be carried out in V-bottom 96-well plates. Serialtwofold dilutions of each sample in PBS are incubated for 1 h on icewith an equal volume of a 0.5% suspension of chicken erythrocytes inPBS. Positive wells contain an adherent, homogeneous layer oferythrocytes; negative wells contain a nonadherent pellet.

Physical quantitation of the virus titer can be performed using PCRapplied to viral supernatants (Quinn & Trevor, 1997; Morgan et al.,1990), hemagglutination assays, tissue culture infectious doses (TCID50)or egg infectious doses (EID50).

5.6.4 Toxicity Studies

The toxicity and/or efficacy of the compositions (e.g., immunogenicformulations) of the present invention can be determined by standardpharmaceutical procedures in cell cultures or experimental animals,e.g., for determining the LD50 (the dose lethal to 50% of thepopulation) and the ED50 (the dose therapeutically effective in 50% ofthe population). The dose ratio between toxic and therapeutic effects isthe therapeutic index and it can be expressed as the ratio LD50/ED50.Therapies that exhibit large therapeutic indices are preferred. Whiletherapies that exhibit toxic side effects may be used, care should betaken to design a delivery system that targets such agents to the siteof affected tissue in order to minimize potential damage to uninfectedcells and, thereby, reduce side effects.

The data obtained from the cell culture assays and animal studies can beused in formulating a range of dosage of the therapies for use insubjects. The dosage of such agents lies preferably within a range ofcirculating concentrations that include the ED50 with little or notoxicity. The dosage may vary within this range depending upon thedosage form employed and the route of administration utilized. For anytherapy used in the method of the invention, the therapeuticallyeffective dose can be estimated initially from cell culture assays. Adose may be formulated in animal models to achieve a circulating plasmaconcentration range that includes the IC50 (i.e., the concentration ofthe test compound that achieves a half-maximal inhibition of symptoms)as determined in cell culture. Such information can be used to moreaccurately determine useful doses in subjects (e.g., horses). Levels inplasma may be measured, for example, by high performance liquidchromatography.

Further, any assays known to those skilled in the art can be used toevaluate the prophylactic and/or therapeutic utility of a composition(e.g., vaccine formulation), a combination therapy disclosed herein forviral infection or a condition or symptoms associated therewith, aninfection other than an a viral infection or a condition or symptomassociated therewith, or a condition in which an attenuated chimericvirus of the invention is used as a vector to induce an immune responseto an antigen associated with the condition.

5.7 Specific Embodiments of the Invention

The present invention provides a chimeric avian influenza virus,comprising a fusion protein, having

-   -   (i) an ectodomain comprising a heterologous peptide sequence,        which heterologous sequence comprises at least one epitope of a        protective antigen of an infectious agent, other than influenza,        or of an antigen associated with a disease fused to    -   (ii) a transmembrane and cytoplasmic domain of a glycoprotein        encoded by an essential gene of an influenza virus,        wherein the fusion protein is incorporated into an avian        influenza virus, in which the function of the essential gene is        supplied by the fusion protein or by the glycoprotein native to        the avian influenza virus. In certain embodiments, the essential        gene of an influenza virus is a hemagglutinin (HA) gene. In        other embodiments, the essential gene of an influenza virus is a        neuraminidase (NA) gene. In certain embodiments, the chimeric        avian influenza virus is attenuated. In accordance with these        embodiments, the chimeric avian influenza virus may be        attenuated by mutations in the NS1 gene.

The present invention provides a chimeric avian influenza virus,comprising a fusion protein, having

-   -   (i) an ectodomain of an NDV HN protein fused to    -   (ii) a transmembrane and cytoplasmic domain of an influenza        virus NA protein,        wherein the fusion protein is incorporated into an avian        influenza virus, in which the function of the NA protein is        supplied by the fusion protein or by the glycoprotein native to        the avian influenza virus. In certain embodiments, the chimeric        avian influenza virus is attenuated. In accordance with these        embodiments, the chimeric avian influenza virus may be        attenuated by mutations in the NS1 gene.

The present invention provides an attenuated chimeric influenza virus,comprising a fusion protein, having

-   -   (i) an ectodomain comprising a heterologous peptide sequence,        which heterologous sequence comprises at least one epitope of a        protective antigen of an infectious agent, other than influenza,        or of an antigen associated with a disease of a protective        antigen of an infectious agent, other than influenza fused to    -   (ii) a transmembrane and cytoplasmic domain of a glycoprotein        encoded by an essential gene of an influenza virus,        wherein the fusion protein is incorporated into an attenuated        influenza virus, in which the function of the essential gene is        supplied by the fusion protein or by the glycoprotein native to        the attenuated influenza virus. In certain embodiments, the        essential gene of an influenza virus is a hemagglutinin (HA)        gene. In other embodiments, the essential gene of an influenza        virus is a neuraminidase (NA) gene.

The present invention provides a chimeric NDV, comprising a fusionprotein, having

-   -   (i) an ectodomain comprising a heterologous peptide sequence,        which heterologous sequence comprises at least one epitope of a        protective antigen of an infectious agent, other than NDV, or of        an antigen associated with a disease fused to    -   (ii) a transmembrane and cytoplasmic domain of a glycoprotein        encoded by an essential gene of an NDV,        wherein the fusion protein is incorporated into an NDV, in which        the function of the essential gene is supplied by the fusion        protein or by the glycoprotein native to the NDV.

The present invention provides a chimeric avian influenza virus,comprising a packaged influenza virus NA segment encoding aneuraminidase fusion protein, in which the NA open reading frame ismodified so that the nucleotides encoding the NA ectodomain are replacedby nucleotides encoding an ectodomain of a neuraminidase antigen of aninfectious agent other than influenza that is anchored by theN-terminus, so that the neuraminidase fusion protein is expressed andincorporated into the chimeric avian influenza virus.

The present invention provides a chimeric avian influenza virus,comprising a packaged influenza virus HA segment encoding ahemagglutinin fusion protein, in which the HA open reading frame ismodified so that the nucleotides encoding the HA ectodomain are replacedby nucleotides encoding an ectodomain of a hemagglutinin antigen of aninfectious agent other than influenza that is anchored by theC-terminus, so that the hemagglutinin fusion protein is expressed andincorporated into the chimeric avian influenza virus.

The present invention provides a chimeric avian influenza virus,comprising a packaged bicistronic influenza virus HA segment,comprising:

-   -   (a) a first open reading frame that encodes an avian influenza        hemagglutinin protein, and    -   (b) a second open reading frame that encodes a hemagglutinin        fusion protein, in which the nucleotides encoding the        hemagglutinin ectodomain are replaced by nucleotides encoding a        heterologous peptide sequence, which heterologous sequence        comprises at least one epitope of a protective antigen of an        infectious agent, other than influenza, or of an antigen        associated with a disease that is anchored by the C-terminus, so        that both the influenza hemagglutinin and the fusion protein are        expressed and incorporated into the chimeric avian influenza        virus.

The present invention provides a chimeric avian influenza virus,comprising a packaged bicistronic influenza virus NA segment,comprising:

-   -   (a) a first open reading frame that encodes an avian influenza        neuraminidase protein, and    -   (b) a second open reading frame that encodes a neuraminidase        fusion protein, in which the nucleotides encoding the        neuraminidase ectodomain are replaced by nucleotides encoding a        heterologous peptide sequence, which heterologous sequence        comprises at least one epitope of a protective antigen of an        infectious agent, other than influenza, or of an antigen        associated with a disease that is anchored by the N-terminus, so        that both the influenza neuraminidase and the fusion protein are        expressed and incorporated into the chimeric avian influenza        virus.

The present invention provides a chimeric avian influenza virus,comprising a packaged influenza virus NA segment encoding aneuraminidase fusion protein, in which the NA open reading frame ismodified so that the nucleotides encoding the NA ectodomain are replacedby nucleotides encoding an ectodomain of an HN antigen of NDV, so thatthe neuraminidase fusion protein is expressed and incorporated into thechimeric avian influenza virus.

In certain embodiments, the chimeric avian influenza virus of paragraphs209-211 and 213-217 which comprises a packaged NS1 gene segment encodinga modified NS1 protein that reduces the cellular interferon antagonistactivity of the virus. In other embodiments, the chimeric avianinfluenza virus of paragraphs 209-211 and 213-217 which comprises an HAsegment having an open reading frame modified to remove thehemagglutinin polybasic cleavage site. In yet other embodiments, thechimeric avian influenza virus of paragraph 215, in which the first openreading frame is modified to remove the hemagglutinin polybasic cleavagesite.

The present invention provides a recombinant nucleic acid molecule(e.g., recombinant DNA molecules) encoding the NA segment of paragraphs213 and 216. The present invention also provides recombinant nucleicacid molecules (e.g., recombinant DNA molecules) encoding the HA segmentof paragraphs 214-215.

The present invention provides methods for propagating the chimericavian influenza viruses of paragraphs 209-211 and 213-218, comprisingculturing the chimeric avian influenza viruses in an embryonated egg ora cell line that is susceptible to avian influenza virus infection. Thepresent invention also provides methods for producing an immunogenicformulation, the method comprising:

-   (a) propagating the chimeric avian influenza virus of paragraphs    209-211 and 213-218 in an embryonated egg or a cell line that is    susceptible to avian influenza virus infection; and-   (b) collecting the progeny virus,    wherein the virus is grown to sufficient quantities and under    sufficient conditions that the virus is free from contamination,    such that the progeny virus is suitable for use in an immunogenic    formulation, e.g., vaccine formulation.

The present invention provides an attenuated chimeric influenza virus,comprising a packaged influenza virus NA segment encoding aneuraminidase fusion protein, in which the NA open reading frame ismodified so that the nucleotides encoding the NA ectodomain are replacedby nucleotides encoding an ectodomain of a neuraminidase antigen of aninfectious agent other than influenza that is anchored by theN-terminus, so that the neuraminidase fusion protein is expressed andincorporated into the attenuated chimeric avian influenza virus.

The present invention provides an attenuated chimeric influenza virus,comprising a packaged influenza virus HA segment encoding ahemagglutinin fusion protein, in which the HA open reading frame ismodified so that the nucleotides encoding the HA ectodomain are replacedby nucleotides encoding an ectodomain of a hemagglutinin antigen of aninfectious agent other than influenza that is anchored by theC-terminus, so that the hemagglutinin fusion protein is expressed andincorporated into the attenuated chimeric influenza virus.

The present invention provides an attenuated chimeric avian influenzavirus, comprising a packaged bicistronic influenza virus HA segment,comprising:

-   (a) a first open reading frame that encodes an avian influenza    hemagglutinin protein, and-   (b) a second open reading frame that encodes a hemagglutinin fusion    protein, in which the nucleotides encoding the hemagglutinin    ectodomain are replaced by nucleotides encoding a heterologous    protein, said protein containing an epitope of an ectodomain of a    protective antigen of an infectious agent other than influenza or of    an antigen that is associated with a disease, said fusion protein    anchored by the C-terminus,    so that both the influenza hemagglutinin and the fusion protein are    expressed and incorporated into the attenuated chimeric influenza    virus.

The present invention provides an attenuated chimeric influenza virus,comprising a packaged bicistronic influenza virus NA segment,comprising:

-   (a) a first open reading frame that encodes an avian influenza    neuraminidase protein, and-   (b) a second open reading frame that encodes a neuraminidase fusion    protein, in which the nucleotides encoding the neuraminidase    ectodomain are replaced by nucleotides encoding heterologous    protein, said protein containing an epitope of an ectodomain of a    protective antigen of an infectious agent other than influenza or of    an antigen that is associated with a disease, said fusion protein    anchored by the N-terminus,    so that both the influenza neuraminidase and the fusion protein are    expressed and incorporated into the attenuated chimeric influenza    virus.

In certain embodiments, the attenuated chimeric influenza virus ofparagraphs 221-224 which comprises a packaged NS1 gene segment encodinga modified NS1 protein that reduces the cellular interferon antagonistactivity of the virus. In certain other embodiments, the attenuatedchimeric influenza virus of paragraphs 221-224 which comprises an HAsegment having an open reading frame modified to remove thehemagglutinin polybasic cleavage site. In other embodiments, theattenuated chimeric influenza virus of paragraph 223, in which the firstopen reading frame is modified to remove the hemagglutinin polybasiccleavage site.

The present invention provides recombinant DNA molecules encoding the NAsegment of paragraphs 221 and 224. The present invention also providesrecombinant DNA molecules encoding the HA segment of paragraphs 222-223.

The present invention provides methods for propagating the attenuatedchimeric influenza viruses of paragraphs 221-225, comprising culturingthe attenuated chimeric influenza viruses in an embryonated egg or acell line that is susceptible to avian influenza virus infection. Thepresent invention also provides methods for producing an immunogenicformulation, the method comprising:

-   (a) propagating the attenuated chimeric influenza virus of    paragraphs 211 and 2221-225 in an embryonated egg or a cell that is    susceptible to attenuated influenza virus infection; and-   (b) collecting the progeny virus,    wherein the virus is grown to sufficient quantities and under    sufficient conditions that the virus is free from contamination,    such that the progeny virus is suitable for use in an immunogenic    formulation, e.g., vaccine formulation.

The present invention provides a chimeric NDV, comprising a packagedgenome comprising a nucleotide sequence encoding an F protein-fusionprotein having the transmembrane and cytoplasmic domains of an F proteinand the ectodomain of an antigen of an infectious agent other than NDVthat is anchored by the C terminus, so that the F protein-fusion proteinis expressed and incorporated into the chimeric NDV.

The present invention provides a chimeric NDV, comprising a packagedgenome comprising a nucleotide sequence encoding an HN fusion proteinhaving the transmembrane and cytoplasmic domains of an HN protein andthe ectodomain of an antigen of an infectious agent other than NDV thatis anchored by the N-terminus, so that the HN fusion protein isexpressed and incorporated into the chimeric NDV.

In certain embodiments, the genome of the chimeric NDV of paragraphs 213and 228-229 comprises a nucleotide sequence encoding an F protein, sothat the F protein is expressed and incorporated into the chimeric NDVin addition to the F protein-fusion protein. In other embodiments, thenucleotide sequence encoding the NDV F protein-fusion protein replacesthe nucleotide sequence encoding the NDV F protein and the Fprotein-fusion protein supplies the function of the F protein for thechimeric NDV of paragraph 228.

In certain embodiments, the genome of the chimeric NDV of paragraph 212and 223-224 comprises a nucleotide sequence encoding an HN protein, sothat the HN protein is expressed and incorporated into the chimeric NDV.In other embodiments, the nucleotide sequence encoding the HN fusionprotein replaces the nucleotide sequence encoding the NDV HN protein andthe HN fusion protein supplies the function of the HN protein for thechimeric NDV of paragraph 229.

The present invention provides methods for propagating the chimeric NDVsof paragraphs 212 and 228-229, comprising culturing the chimeric NDVs inan embryonated egg or a cell line that is susceptible to NDV infection.The present invention also provides a method for producing animmunogenic formulation, the method comprising:

-   (a) propagating the chimeric NDV of paragraphs 212 and 228-229 in an    embryonated egg or a cell; and-   (b) collecting the progeny virus,    wherein the virus is grown to sufficient quantities and under    sufficient conditions that the virus is free from contamination,    such that the progeny virus is suitable for for use in an    immunogenic formulation, e.g., vaccine formulation.

The present invention provides embryonated eggs comprising the chimericviruses of paragraphs 209-210, 212-218 and 228-229. The presentinvention also provides cell lines comprising the chimeric viruses ofparagraphs 209-210, 212-218 and 228-229. The present invention furtherprovides immunogenic formulations comprising the chimeric viruses ofparagraphs 209-210, 212-218 and 228-229.

The present invention provides embryonated egg comprising the attenuatedchimeric viruses of paragraphs 211 and 221-225. The present inventionalso provides cell lines comprising the attenuated chimeric viruses ofparagraphs 211 and 221-225. The present invention further providesimmunogenic formulations comprising the attenuated chimeric viruses ofparagraphs 211 and 221-225.

The present invention provides methods of inducing an immune responsetwo infectious agents in an avian, the method comprising administeringan effective amount of a chimeric avian influenza virus of paragraphs209-210 and 213-218. The present invention also provides methods ofinducing an immune response two infectious agents in an avian, themethod comprising administering an effective amount of a chimeric NDV ofparagraphs 212 and 228-229. The present invention further providesmethods for inducing an immune response two infectious agents in asubject, the method comprising administering an effective amount of anattenuated chimeric influenza virus of paragraphs 211 and 221-225. Incertain embodiments, the subject is a human subject. In otherembodiments, the subject is a non-human mammal (e.g., a pig, horse, dog,cat, or bovine). In yet other embodiments, the subject is an aviansubject.

6. EXAMPLES 6.1 Engineering of Chimeric Avian Influenza Virus Presentinga Newcastle Disease Virus Epitope

The following example describes the production of a exemplary chimericavian influenza virus. In particular, the example describes theengineering of an avian influenza virus, Influenza A/Vietnam/1203/04(H5N1), to express and incorporate in its virion a fusion proteincomprising the transmembrane and cytoplasmic domains of the avianinfluenza virus NA protein and the ectodomain of the NDV HN protein. Thefusion protein functionally replaces the avian influenza virus NAprotein.

6.1.1 Materials and Methods

6.1.1.1 Construction of Plasmids

All plasmid constructs for use in plasmid-only rescue of recombinantviruses, were cloned using the same strategy. Full length cDNAs of viralsegments were amplified using PCR with primers that included SapIrestriction sites, which allowed the insertion of the PCR product intothe SapI sites of the pPolI-SapI-Rb plasmid (Flandorfer et al., 2003, J.Virol. 77:9116-9123; Nakaya et al., 2001, J. Virol. 75:11868-11873; bothof which are incorporated herein by reference in their entireties).Sequences of all PCR inserts were confirmed (Mount Sinai DNA sequencingfacility, NY), and nucleotide changes that had been introduced by PCRwere corrected using a QuickChange XL site-directed mutagenesis kit(Stragene, La Jolla, Calif.) when appropriate. The GenBank sequences forthe Influenza A/Vietnam/1203/04 (H5N1), Influenza A/WSN/33 (WSN) and NDVare provided in Table 2

TABLE 2 GenBank Accession Numbers of Virus Segments Virus SegmentGenbank Accession No. H5N1 NS AY651553 (SEQ ID NO: 1) M AY651388 (SEQ IDNO: 2) NP AY651499 (SEQ ID NO: 3) HA AY818135 (SEQ ID NO: 4) NA AY651447(SEQ ID NO: 5) PA AY818132 (SEQ ID NO: 6) PB1 AY818129 (SEQ ID NO: 7)PB2 AY651719 (SEQ ID NO: 8) WSN NA L25817 (SEQ ID NO: 9) NDV B1 HNAF309418 (SEQ ID NO: 10)

6.1.1.2 Construction of Chimeric Viral Segment

A cDNA encoding the NDV B1 HN ectodomain and the cytoplasmic tail (CT)and transmembrane (TM) domains of the neuraminidase (NA) of influenzaA/WSN/33 (A/Vietnam/1203/04-A/WSN/33 NA_((CT+TM))-NDV B1 HN_((ecto)))was constructed using recombinant techniques well known in the art. Theconstruct encodes 19 nucleotides of the 3′ noncoding region of the WSNNA vRNA, nucleotides encoding amino acids 1-36 (108 nucleotides) of theNA coding region, corresponding to the cytoplasmic tail andtransmembrane domains of the NA protein plus the first amino acid of theNA ectodomain, followed by nucleotides encoding amino acids 51-568 ofthe NDV B1 HN protein (HN ectodomain), two sequential stop codons, 157untranslated nucleotides of the WSN NA reading frame and the 5′noncoding region of the WSN vRNA (FIG. 1).

6.1.1.3 Construction of Plasmid Constructs Encoding Chimeric H5N1-NDV

Plasmid constructs were created in order to produce, by plasmid onlyrescue, a chimeric virus based on H5N1 (the host virus) engineered topresent an NDV surface glycoprotein. The segment of H5N1 encoding thesurface glycoprotein NA was selected to be replaced with a recombinantsegment comprising a nucleotide sequence encoding the CT and TM domainsof the NA protein plus the first amino acid of the NA ectodomain ofA/WSN/33 and the ectodomain of the HN protein of NDV-B1. The fusionprotein, A/Vietnam/1203/04-A/WSN/33 NA_((CT+TM))-NDV B1 HN_((ecto)),supplies the neuraminidase activity for the chimeric avian influenzavirus. See FIG. 1 for a schematic of the chimeric segment.

The remaining seven segments of H5N1 listed in Table 2 (NS, M, NP, HA,PA, PB1 and PB2) were cloned into pPol1 to produce pPol1VN1203-NS,pPol1VN1203-M, pPol1 VN1203-NP, pPol1 VN1203-HA, pPol1 VN1203-PA,pPol1VN1203-PB1 and pPol1VN1203-PB2, respectively. To ensure attenuationof the chimeric H5N1 virus, the segment encoding H5N1 HA was altered toconvert the native polybasic amino acid sequence immediately before theHA cleavage site (nucleotides 1013-1039 of the H5N1 HA coding sequence)to a consensus sequence based on avirulent avian strains of influenza AH5. The amino acid sequence in this region was altered from QRERRRKKRG(SEQ ID NO:11; amino acids 2-11 of SEQ ID NO:14) to QRETRG (SEQ IDNO:12; amino acids 2-7 of SEQ ID NO:16), replacing the underlined aminoacids with threonine (FIG. 2). The codon usage in this region wasfurther altered to reduce the number of adenosine residues in orderminimize the chance of reintroduction of adenosine residues in thissequence by polymerase slippage and the resultant introduction of basicamino acid residues into the HA cleavage site. Only synonymous mutationswere introduced into the avirulent HA sequence (FIG. 3). The resultantsegment encoding the altered HA glycoprotein, correspondinglow-virulence avian influenza A strains, was cloned in to a pPol1plasmid as previously described, pPol1VN1203-HALO. With the exception ofPB1 and PB2, the gene products encoded by the segments of H5N1 wereunaltered from the genbank sequences. The sequences of PB1 and PB2 werealtered as a result of the introduction of the SapI restriction sites. Anon-synonymous substitution with the nucleotide guanine at position 32of the coding sequence of PB1 resulted in a lysine to arginine mutation;the non-synonymous substitution with the nucleotide thymine at position1393 of the coding sequence of PB2 resulted in a proline to serinemutation. All gene products of H5N1 have an adenosine residue atposition 4 of the vRNA.

In addition to the plasmid construct encoding wild-type H5N1 NS,pPol1VN1203-NS, three pPol1 constructs encoding differently truncatedversions of the H5N1 NS gene segment were also generated. The additionalconstructs encoding altered versions of the NS segment may be of use infurther attenuating the resulting chimeric virus (see, e.g., U.S. Pat.No. 6,669,943, which is incorporated herein by reference in itsentirety). The three constructs varied in the number of amino acids ofthe NS1 protein (from the amino terminus) that are expressed by theplasmid construct. pPol1VN1203 NS1-126, pPol1VN1203 NS1-99 andpPol1VN1203 NS1-73 thus encode only the first 126, only the first 99 andonly the first 73 amino acids as counted from the amino terminus of thewild type NS1 protein, respectively. The mutagenesis to generatetruncated constructs did not affect the open reading frame of NEP (FIG.4A, FIG. 4B, FIG. 4C, and FIG. 4D).

6.1.1.4 Rescue of Infectious Virus from Plasmid Constructs

Recombinant, chimeric viruses of the invention are rescued by any meansdescribed herein or known in the art. For example, 293T, HEp-2 or A549cells may be transfected with eight of the described pPol1 plasmids,selected to achieve a desired level of viral attenuation and so that alleight segments are represented, i.e., the cells are transfected withpPol1VN WSN-NA_((CT+TM))-NDV B1 HN_((ecto)); pPol1VN1203-HA orpPol1VN1203-HALO; pPol1VN1203-NS, pPol1VN1203 NS1-126, pPol1VN1203NS1-99 or pPol1VN1203 NS1-73; pPol1 VN1203-M; pPol1 VN1203-NP; pPol1VN1203-PA; pPol1VN1203-PB1 and pPol1VN1203-PB2. The cells are furthertransfected with eukaryotic expression plasmids encoding NA, PA, PB1 andPB2, which are required for replication and transcription of the vRNAs.After overnight incubation, the transfected cells may be co-culturedwith chicken embryo fibroblasts to amplify the produced virus. After afurther 2 to 3 day incubation, the supernatant of the co-culture may beinjected into the allantoic cavities of 9- or 10-day old embryonatedchicken eggs for propagation. For attenuated viruses, 7-day old eggs,which do not have a competent interferon system may be used. Virusgrowth may be confirmed by assaying the harvested allantoic fluid forhemagglutination according to standard protocols known in the art.

6.2 Engineering of Chimeric Newcastle Disease Virus Presenting a ForeignEpitope

The following example describes the production of exemplary chimericNDVs. In particular, the example describes the engineering of a chimericNDV to express and incorporate into its virion a fusion proteincomprising the transmembrane and cytoplasmic domains of a necessaryprotein of NDV and the ectodomain of an avian influenza virus. Theexample demonstrates that such a chimeric virus induces protectionagainst subsequent infection by both influenza virus and NDV.

The example also describes the engineering of an exemplary NDV toexpress and incorporate into its virion a fusion protein comprising thecytoplasmic domain of the NDV F protein and the ectodomain andtransmembrane domain of human keratinocyte growth factor receptor(KGFR).

6.2.1 Materials and Methods

6.2.1.1 Cell Lines

MDCK, HEp-2 and A549 cells were grown in Dulbecco's Modified EagleMedium (DMEM) supplemented with 10% fetal calf serum and 1%penicillin/streptomycin. The full length cDNA of the Hitchner B1 strainof NDV has been published under genbank accession number AF375823(Nakaya et al., 2001, J. Virol. 75:11868-11873, which is incorporatedherein by reference in its entirety).

6.2.1.2 Construction of Plasmids

The engineering of recombinant cDNA of NDV to encode a foreign proteinhas been described (Nakaya et al., 2001, J. Virol. 75:11868-11873).Briefly, the full length cDNA of NDV is introduced into a plasmidbetween the T7 promoter and the hepatitis delta virus (HDV) ribozyme andT7 terminator to create pNDV/B1. The NDV cDNA has a XbalI siteengineered between the P and M genes that allows the introduction offoreign sequences as an extratransciptional unit into the NDV genome(FIG. 5). All inserted genes are engineered to contain, sequentially, agene end; 5′-TTAGAAAAAA-3′ (SEQ ID NO:18); intercistronic nucleotide T;and the gene start sequence; 5′-ACGGGTAGAA-3′ (SEQ ID NO:19) (the GE/GSsequence).

rNDV/B1-KGFR, rNDV/B1-KGFR/F-CT, and rNDV/B1-H7HA/F-TMCT viruses weregenerated by reverse genetics from the full-length cDNA copies derivedfrom the NDV Hitchner B1 strain. To construct these viruses, the KGFR orH7 HA (HA protein from influenza A subtype H7N2) ORF was cloned as anextra transcriptional unit between the P and M genes of NDV/B1 cDNA, asdescribed for other ORFs (Nakaya et al., 2001, J. Virol. 75:11868-11873and Nakaya et al., 2004, J. Virol. 78:9366-9375, both of which arehereby incorporated by reference in their entireties). KGFR and H7 HAare both transmembrane proteins, each comprising a TM and CT domain. Inthe KGFR/F-CT construct, the CT domain of the KGFR protein was replacedby that of the F protein of NDV. In the H7 HA/F-TMCT construct, the TMand CT domains of the H7 HA protein were replaced by those of the Fprotein of NDV. The recombinant NDV viruses were rescued from cDNA andpropagated using standard techniques well known in the art (see, e.g.,Swayne et al., 2003, Avian Dis. 47: 1047-1053 and Nakaya et al., 2001,both of which are hereby incorporated by reference in their entireties).The insertion of the new transcriptional units in the recombinantviruses was confirmed by reverse transcription PCD followed bysequencing analysis.

For example, the ectodomain (ECTO) of the H5 HA gene was produced by PCRusing the following primers (which include the GE/GS sequence):NheI-H5HA P, 5′-CG GCT AGC TTAGAAAAAA T ACGGTAGAA GTGAA ACTAGT CC GCCACC ATG GAA AGA ATA GTG ATT GCC TTT GCA-3′ (SEQ ID NO:20) and HpaI-H5HAP, 5′-CG GTT AAC CTG ATA AGC CCC CAT TGA TTC TAA T-3′ (SEQ ID NO:21).The H5 HA_(ecto) PCR fragment was digested with NheI and HpaI and clonedinto pSL1180 (Amersham Pharmacia Biotech) (pSLH5HA_(ecto)). The TM andCT of the NDV F gene were also amplified by PCR using the followingprimers, HpaI-NDVF(TM+CYTO) P, 5′-CG GTT AAC CTC ATT ACC TAT ATC GTT TTGACT-3′ (SEQ ID NO:22), SacI-NheI-NDVF(TM+CYTO) M, 5′-CG GAG CTC AA GCTAGC TTA TCA CAT TTT TGT AGT GGC TCT CAT CTG-3′ (SEQ ID NO:23). To fusewith H5 HA_(ecto), the TM and CT of the NDV F gene were digested withHpaI and SacI and then cloned into pSLH5HA_(ecto) to obtain the hybridfusion gene. Finally, the plasmid containing the hybrid H5 HA gene wasdigested with NheI and cloned between the P and M genes of the rNDVcDNA.

6.2.1.3 Western Blot and Biological Analysis

Viruses from cell or allantoic extracts were purified byultracentrifugation through a 30% sucrose cushion. Levels ofincorporated protein were monitored by western blot analysis usingspecific antibody and routine techniques.

The ability of the chimeric NDV to present the non-viral protein KGFR invivo was determined by immunizing BALB/c mice with 3×10⁷ pfu of thechimeric virus intraperitoneally, followed by a booster immunizationusing the same dose three weeks later. Two weeks after the secondimmunization, sera from inoculated animals was tested for the presenceof antibodies to KGFR by immunostaining MDCK cells transfected with aplasmid encoding KGFR.

An in vivo system was designed to evaluate whether immunization with therNDV comprising the hybrid H7 HA/F-TMCT was able to provide protectionagainst subsequent infection by H7 or NDV. Two-week old chicks wereimmunized by eye-drop method with 100 μl of three vaccines, rNDV,rNDV-H7 HA/F-TMCT and Sham. At 4 weeks of age, 100 μl comprising10^(5.1) mean embryo infectious dose of HP AIV (A/Steele/ACC-10/59[H7N7]) was administered through the choanal slit. The birds wereobserved for signs and lesions of HP AIV infection. Mortality wasrecorded, and all survivors were euthanized by sodium pentobarbital (100mg/kg) at 6 weeks of age.

6.2.2 Results

6.2.2.1 Presentation of KGFR by Chimeric NDV Expressing KGFR orKGFR/F-CT

Chimeric viruses rNDV/B1-KGFR and rNDV/B1-KGFR/F-CT were grown in theallantoic cavity of 10-day old chicken embryonated eggs. Purifiedviruses were tested for the presence of KGFD or KGFR/F-CT by Westernblot analysis using a murine anti-KGFR antibody. A positive response wasdetected in the samples isolated from eggs inoculated withrNDV/B1-KGFR/F-CT but not with rNDV/B1-KGFR (FIG. 6).

Each of these chimeric viruses were also used to immunize three BALB/cmice. Sera from the immunized animals was assayed for the presence ofKGFR antibodies. Animals immunized with rNDV/B1-KGFR virus did notdevelop detectable levels of KGFR antibodies using this assay. Incontrast, all three animals immunized with rNDV/B1-KGFR/F-CT virus werepositive by this assay for the presence of KGFR antibodies.

6.2.2.2 Protection Against 117 Infection by Immunization with rNDV-117HA/F-TMCT

The TM and CT domains of the wild-type H7 HA were replaced by the TM andCT domains of the NDV F protein to generate a hybrid HA protein,H7HA_(ecto)-NDV/F_((TM+CT)). In a Western blot analysis, both thecontrol rNDV expressing the complete ORF of H7 HA, rNDV-H7HA, and thechimeric rNDV expressing the hybrid H7HA_(ecto)-NDV/F_((TM+CT)),rNDV-H7HA_(ecto)-NDV/F_((TM+CT)), generated a positive reaction to theH7 antibody; however, the signal from rNDV-H7HA_(ecto)-NDV/F_((TM+CT))was visibly many times stronger (FIG. 7). When chicks immunized oncewith rNDV-H7HA_(ecto)-NDV/F_((TM+CT)) were subsequently challenged witha lethal dose of H7 influenza, 9 out of 10 (90%) of the immunized chickssurvived. When chicks immunized once withrNDV-H7HA_(ecto)-NDV/F_((TM+CT)) were subsequently challenged with alethal dose of NDV, 10 out of 10 (100%) of the immunized chickssurvived.

6.3 Engineering of Chimeric Newcastle Disease Virus Presenting a ForeignEpitope

The following example describes the production of chimeric modifiedNDVs. In particular, a recombinant NDV was produced to improve virulenceof the NDV backbone used in Example 6.2. The example demonstrates thatthe improved virulence of the rNDV also improved the immunogenicity ofimmunogenic formulations comprising chimeric viruses based on the rNDV.

6.3.1 Materials and Methods

Unless otherwise stated all Materials and Methods described in thesection are identical to those described and exemplified in Example 6.2,supra.

6.3.1.1 Generation of rNDVs with a Modified Cleavage Site in their FProteins

Recombinant NDV viruses rNDV/F2aa and rNDV/F3aa viruses, which have twoor three amino acid mutations at the F cleavage site of NDV Hitchner B1strain were generated by reverse genetics. Briefly, to generaterNDV/F2aa, the PCR fragment was generated by using primers, forward:F2aa-1(+) 5′-GGA TCC CGG TTG GCG CCC TCC AGG (SEQ ID NO:24), and reverse

F2aa-1(−) (SEQ ID NO: 25) 5′-AAG GCG CCt CTG TCT CCg CCC TCC AGA TGTAGT CAC AG-3′and the full-length NDV B1 clone, plasmid pT7NDV/B1, as template. Thenext PCR fragment was generated by using primers, forward

F2aa-2(+) (SEQ ID NO: 26) 5′-GGc GGA GAC AGa GGC GCC TTA TAG GCG CCATTA TTG G-3′,and reverse F2aa-2(−) 5′-CCA TAT TCC CAC CAG CTA GAT TGT-3′ (SEQ IDNO:27) and the pT7NDV/B1 as template. The nucleotides shown in lowercase are mutated to modify the amino acid sequence of the cleavage siteof the F protein from that of the NDV/B1 strain (GGRQGR↓L) to GRRQRR↓L.These two overlapping PCR fragments (the overlap is underlined in theprimer sequences) were combined by PCR using primers, F2aa-1(+) andF2aa-2(−). The resulting PCR fragment, which contains the entire F genewas cloned into pSL1180 (Amersham Pharmacia Biotech) and named pSLF2aa.The StuI-NotI fragment (nt 4646 to 4952) of pSLF2aa was excised toreplace the corresponding fragment in the pT7NDV/B1 plasmid, resultingin the formation of the pT7NDV/F2aa plasmid, which was used to generaterNDV/F2aa virus by reverse genetics. For generation of rNDV/F3aa, PCRmutagenesis was performed by the same strategy as described above usingprimers, forward,

F3aa-1(+) (SEQ ID NO: 28) 5′-GGA TCC CGG TTG GCG CCC TCC AGG-3′;reverse, F3aa-1(−) (SEQ ID NO: 29)5′-AAa GCG CCt CTG TCT CCg CCC TCC AGA TGT AGT CAC AG-3′; forward,F3aa-2(+) (SEQ ID NO: 30) 5′-GGc GGA GAC AGa GGC GCt TTA TAG GCG CCATTA TTG G-3′; reverse, F3aa-2(−) (SEQ ID NO: 31)5′-CCA TAT TCC CAC CAG CTA GAT TGT-3′(mutated nucleotides are indicated with lower case) and the pT7NDV/B1 astemplate. These two overlapping PCR fragments (the overlap region isunderlined in the primer sequences) were combined by PCR using primersF3aa-1(+) and F3aa-2(−), resulting in modification of the cleavage sitefrom GGRQGR↓L to GRRQRR↓F. The StuI-NotI fragment (nt 4646 to 4952) ofpSLF3aa was excised to replace the corresponding fragment in thepT7NDV/B1 plasmid, resulting in the formation of the pT7NDV/F3aaplasmid, which was used to generate rNDV/F3aa virus.

6.3.1.2 Generation of a Fusogenic rNDV Vector Expressing the Chimeric117 HA Protein.

To construct the chimeric H7 HA gene as an extra transcriptional unit ofthe rNDV/F3aa genome, the fragment containing the transmembrane (TM) andthe cytoplasmic tail (CYTO) of the NDV F gene was initially produced byPCR using primers, HpaNDV F(TM+CYTO)P, 5′-cgGT TAA CCT CAT TAC CTA TATCGT TTT GAC T-3′ (SEQ ID NO:32) and SacNheNDVF(TM+CYTO)M, 5′-cg GAG CTCAAG CTA GCT TAT CAC ATT TTT GTA GTG GCT CTC ATC TG-3′ (SEQ ID NO:33) andthe plasmid containing the NDV F gene as a template. This PCR productwas digested with Sac I and Hpa I and then cloned into the plasmid,pNhe-NDV-GE/GS possessing the gene end and the gene start signal of NDV,resulting in the formation of plasmid, pNhe-NDV-GE/GS-NDVF(TM+CYTO). Asthe next step, allowing the connection of the fragment containing H7 HAectodomain with the fragment of the TM and CYTO region of the NDV F, theH7HA ectodomain was produced by PCR using the primers, SpeH7(ECTO)P,5′-cgACT AGT CCG CCA CCA TGA ACA CTC AAA TTC TGG CAT TCA T-5′ (SEQ IDNO:34), HpaH7(ECTO)M, 5′-cgG TTA ACG TCT TTG TAT CCA CTA CTC AAT TTCAC-3′ (SEQ ID NO:35) and plasmid containing H7 HA gene fromA/chicken/NY/13142-5/94(H7N2) as template. This PCR product was digestedwith Spe I and Hpa I and then inserted into the cassette plasmid,pNhe-NDV-GE/GS-NDVF(TM+CYTO). In a final step, the cassette plasmid,pNhe-NDV-GE/GS-NDV F(TM+CYTO) was digested with Nhe I to cut out thechimeric H7 HA gene. This fragment DNA was cloned between the P and Mgenes of pT7NDV/F3aa, forming pT7NDV/F3aa-chimericH7. The rNDV/F3aavirus expressing the chimeric H7 HA protein was then rescued frompT7NDV/F3aa-chimericH7 using methods describe, supra.

6.3.1.3 Viral Growth Kinetics

rNDV/B1, rNDV/F2aa, rNDV/F3aa, rNDV/B1-H7, or rNDV/F3aa-chimericH7viruses (100 PFU/egg) were inoculated into 10-day-old embryonatedchicken eggs. Allantoic fluids were harvested to determine viral titersat different time points (24 hrs, 48 hrs, and 72 hrs). The 50% tissueculture infective dose (TCID₅₀) of each virus present in the allantoicfluid was determined by immunofluorescence assay (IFA). For thispurpose, ninety-six well plates containing Vero cells were infected withserial 10-fold dilutions of the samples, and the presence of NDVproteins or chimeric H7 HA protein was determined by IFA.

6.3.2 Immunofluorescence Assays.

6.3.2.1 Immunofluorescence Assays

MDCK cells infected with transfectant influenza virus were fixed andpermeabilized with ice cold methanol. Viral antigens were detected withanti-NDV HN monoclonal antibody (7B1), anti-influenza H1 HA monoclonalantibody (2G9) and anti-influenza H5 HA polyclonal serum. For theanalysis of NDV growth and viral protein expression, confluent Verocells were infected with the recombinant viruses, and harvested atdifferent time points (24, 48, and 72 hrs). Infected cells were fixedwith 2.5% formaldehyde containing 0.1% Triton X-100. Fixed cells weretreated with anti-rabbit NDV polyclonal antibody or anti-chicken AIV H7polyclonal serum, washed, and stained with fluorescein isothiocyanate(FITC)-conjugated anti-chicken immunoglobulins (DAKO) for AIV H7 HAprotein or Texas Red-conjugated anti-rabbit immunoglobulins (MolecularProbe) for the NDV viral proteins. Viral protein expression was examinedby fluorescence microscopy.

6.3.2.2 Mean Death Time

To check the pathogenicity of recombinant viruses in embryonated chickeneggs, mean death time (MDT) was determined. Briefly, five 10-day-oldembryonated chicken eggs were infected with serial 10-fold dilutions ofviruses. The eggs were incubated at 37° C. and monitored two times dailyfor 7 days. The time to kill embryos was recorded. The highest dilutionthat killed all embryos was determined to be the minimum lethal dose.The MDT was calculated as the mean time for the minimum lethal dose tokill the embryos.

6.3.2.3 Immunization and Challenge of Chickens

White Leghorn chickens were vaccinated once or twice by eyedrop in theconjunctival sac with 10^(5.7-6.1) mean chicken embryo infectious doses(EID₅₀) of rNDV/F3aa-chimericH7, or twice with 10^(5.7-6.3) EID₅₀ ofparental NDV/B1 (pNDV), or twice with sterile tissue culture media(sham) at 2 and 4 weeks-of-age. At 6 weeks-of-age, the chickens werechallenged intranasally with the Fontana strain of velogenic NDV(vvNDV)(10^(5.1) EID₅₀ per bird) or A/Human/Steele/59 (H7N7) HPAI(10^(5.1) EID₅₀ per bird). The survivors were bled and euthanized on 14days post challenge. Hemagglutination inhibition (HI) serological titerswere determined using standard procedures.

6.3.3 Results

6.3.3.1 Generation of Fusogenic rNDV Mutants

To improve the fusogenic characteristics of the rNDV backbone, two rNDVmutants, rNDV/F2aa and rNDV/F3aa viruses, were developed in which thecleavage site of the F protein was replaced with one of two variantmulti-basic cleavage sites, which can be activated by ubiquitouslyexpressed proteases (e.g., furin proteases) (FIG. 8A). Infection ofchicken embryo fibroblast cells (CEF) with rNDV/F2aa and rNDV/F3aa, andnot with rNDV/B1, resulted in syncytia formation in the absence ofexogenously added protease (FIG. 8B). In addition, rNDV/F3aa inducedsyncytia more rapidly in CEF cells than rNDV/F2aa. It was thuspostulated that improved spreading of the virus in immunized animals mayenhance immunogenicity against inserted foreign protein. Thus thefusogenic rNDV/F3aa was selected as a backbone vector to develop abivalent vaccine designed to protect poultry against AIV and

6.3.3.2 Mean Death Time Analysis of rNDV Platform Vectors in EmbryonatedChicken Eggs.

NDV can be classified as highly virulent (velogenic), intermediate(mesogenic), or nonvirulent (lentogenic) on the basis of itspathogenicity for chickens. Since the presence of an F protein with amultibasic cleavage site is known to be an NDV virulence factor, weassessed the pathogenicity of rNDVs with modified F protein in10-day-old embryonated chicken eggs. The mean death time (MDT) ofchicken embryos infected with NDVs correlates with virulence in vivo.Lentogenic strains (causing asymptomatic infections in birds) arecharacterized by MDTs of more than 90 hrs, mesogenic strains (causingrespiratory disease in birds) have MDTs between 60 to 90 hrs, andvelogenic strains (causing severe disease in birds) have MDTs under 60hrs. The MDT of rNDV/F2aa was indicative of a lentogenic strain, whilethat of rNDV/F3aa was typical of a mesogenic strain. Neither of thesestrains had MDTs typical of a highly pathogenic (velogenic) strain(Table 3).

TABLE 3 MDT of rNDVs in Embryonated Chicken Eggs Trypsin RequirementInoculation Virus (cell Culture) EID₅₀ MDT, hr rNDV/B1 Yes 10 113 1 122rNDV/F2aa No 10 100 1 104 rNDV/F3aa No 10 80 1 84 rNDV/B1-H7 Yes 10Alive 1 Alive rNDV/3aa- No 10 128 chimericH7 1 140

Based on these data, rNDV/F3aa vector would not represent a threat tobirds and is thus suitable as a backbone to develop a bivalent vaccinefor the protection of poultry against AIV and NDV.

6.3.3.3 Generation of a Fusogenic rNDV Vector Expressing the Ectodomainof AIV HA Protein.

The gene encoding the H7 HA protein from A/chicken/NY/13142-5/94(H7N2)was incorporated into the rNDV/F3aa vector as described supra, resultingin the formation of rNDV/F3aa-chimericH7 (FIG. 9A). The growth kineticof rNDV/F3aa-chimericH7 in embryonated chicken eggs was compared to thatof the parental rNDV/F3aa (FIG. 9B). The virus expressing the chimericH7 HA protein grew more slowly than the virus without the insert andmaximal titers were about a log lower. Interestingly, the MDT of thisvirus was that of a lentogenic strain (128˜140 hrs) (Table 3).Expression of the chimeric H7 HA protein from rNDV/F3aa-chimericH7 wasconfirmed by western blotting of infected Vero cells 36 hrspost-infection (FIG. 9C).

6.3.3.4 Improved Incorporation of AIV 117 HA Protein into rNDV Virions.

To determine if expression of the chimeric H7 HA protein containing theheterologous transmembrane and cytoplasmic tail regions of the NDV Fprotein would be associated with enhanced incorporation into rNDVvirions, rNDV/B1-H7 and rNDV/F3aa-chimericH7 virions were purified asdescribed in §6.3. The amounts of H7 HA protein or NDV viral proteinfrom rNDV/B1-H7 or rNDV/F3aa-chimericH7 were measured by westernblotting using anti-chicken AIV H7 polyclonal antibody or anti-rabbitNDV polyclonal serum. As expected, incorporation of chimeric H7 HAprotein into rNDV virions was significantly increased as compared tothat of wt H7 HA protein (FIG. 9D). This data suggests that thetransmembrane and cytoplasmic tail regions of the NDV F protein play amajor role in the improved incorporation of the foreign protein into theviral surface.

6.3.3.5 Immunization and Challenge of Chickens.

Following one or two vaccinations with rNDV/F3aa-chimericH7, 50-80% ofthe chickens had hemagglutination inhibition (HI) titers to H7 AIV and90-100% of the chickens had HI titers to NDV (Table 4A and B). While allchickens immunized twice with the parental NDV/B1 (pNDV) had HI titersto NDV but none had titers to H7 AIV. All sterile tissue culture media(sham) infected birds lacked HI titers to either virus. When challengedwith vvNDV, 100% of rNDV/F3aa-chimericH7 and pNDV immunized chickenswere protected. By comparison, 90% of rNDV/F3aa-chimericH7 vaccinatedchickens were protected from HPAI H7 virus, but none of pNDV vaccinatedchickens were protected from HPAI H7 virus. By contrast, 100% and 70% ofsham infected birds died when challenged by vvNDV and HPAI H7 virus,respectively. The survivors mounted an amnestic response evident as afour fold or greater rise in HI titer for the respective challenge virusexcept for the three survivors in the sham-HPAI H7 virus challenge groupwhich had no serological evidence of being infected.

TABLE 4A HI Serology of Chickens Immunized with Chimeric Viruses BeforeChallenge AIV/H7 NDV Vaccine Group* antigen antigenrNDV/F3aa-chimericH7, 1X    8/10(11) 10/10(49) rNDV/F3aa-chimericH7, 1X   7/10(10) 10/10(49) rNDV/F3aa-chimericH7, 2X    8/10(13)  9/10(56)rNDV/F3aa-chimericH7, 2X   5/10(9)  9/10(60) pNDV, 2X 0/10 10/10(34)pNDV, 2X 0/10 10/10(56) Sham, 2X 0/10 0/10   Sham, 2X 0/10 0/10  

TABLE 4B HI Serology of Chickens Immunized with Chimeric Viruses AfterChallenge (14 Days post challenge) Challenge No AIV/H7 NDV VaccineGroup* Virus Survivors antigen antigen rNDV/F3aa- vNDV 10/10  9/10(15)10/10(416) chimericH7, 1X rNDV/F3aa- HPAIV 9/10  9/9(2,048) 9/9(37) chimericH7, 1X rNDV/F3aa- vNDV 10/10  7/10(17) 10/10(315) chimericH7, 2XrNDV/F3aa- HPAIV 9/10 8/8(955) 8/8(30)  chimericH7, 2X pNDV, 2X vNDV10/10  0/10    10/10(294) pNDV, 2X HPAIV 0/10 NA NA Sham, 2X vNDV 0/10NA NA Sham, 2X HPAIV 3/10 0/3    0/3    Sham = sterile tissue culturefluid HPAIV = A/human/Steele/59 (H7N7) virus HI serology is shown asnumber of chickens with HI-positive serum/number of chickens vaccinated;parenthetical values are geometric mean titer (GMT) *n = 10 birds pergroup, 1X = one vaccination, 2X = 2 vaccinations The publicationentitled “Engineered Viral Vaccine COnstructs with Dual Specificity:Avian Influenza and Newcastle Disease,” by Man-Seong Park et al., inPNAS 103: 8203-8208 (2006) is incorporated herein by reference in itsentirety.

6.4 Equivalents

The present invention is not to be limited in scope by the specificembodiments described which are intended as single illustrations ofindividual aspects of the invention, and functionally equivalent methodsand components are within the scope of the invention. Indeed, variousmodifications of the invention, in addition to those shown and describedherein will become apparent to those skilled in the art from theforegoing description and accompanying drawings. Such modifications areintended to fall within the scope of the appended claims.

Throughout this application various publications are cited. Theircontents are hereby incorporated by reference into the presentapplication in their entireties for all purposes.

1.-33. (canceled)
 34. A chimeric Newcastle Disease Virus (NDV),comprising a packaged genome comprising a nucleotide sequence encodingan F-fusion protein, wherein the F-fusion protein comprises thetransmembrane and cytoplasmic domains of an NDV F protein and anectodomain of a heterologous protein that is anchored by the C-terminusof the heterologous protein, so that the F-fusion protein is expressedand incorporated into the chimeric NDV, and wherein the heterologousprotein is not a paramyxovirus antigen.
 35. A chimeric Newcastle DiseaseVirus (NDV), comprising a packaged genome comprising a nucleotidesequence encoding an HN-fusion protein, wherein the HN-fusion proteincomprises the transmembrane and cytoplasmic domains of an NDV HN proteinand an ectodomain of a heterologous protein that is anchored by theN-terminus of the antigen, so that the HN protein-fusion protein isexpressed and incorporated into the chimeric NDV, and wherein theheterologous protein is not a paramyxovirus antigen.
 36. The chimericNDV of claim 34 in which the genome comprises a nucleotide sequenceencoding an F protein, so that the F protein is expressed andincorporated into the chimeric NDV.
 37. The chimeric NDV of claim 35 inwhich the genome comprises a nucleotide sequence encoding an HN protein,so that the HN protein is expressed and incorporated into the chimericNDV.
 38. The chimeric NDV of claim 34, wherein the chimeric NDV has anNDV strain LaSota backbone.
 39. The chimeric NDV of claim 35, whereinthe chimeric NDV has an NDV strain LaSota backbone.
 40. The chimeric NDVof claim 34, wherein the transmembrane and cytoplasmic domains of theF-fusion protein are from NDV strain LaSota.
 41. The chimeric NDV ofclaim 35, wherein the transmembrane and cytoplasmic domains of theHN-fusion protein are from NDV strain LaSota.
 42. The chimeric NDV ofclaim 36, wherein the F protein is genetically modified at the cleavagesite, such that fusogenic activity is increased.
 43. The chimeric NDV ofclaim 42, wherein the genetically modified cleavage site comprises amulti-basic cleavage site.
 44. The chimeric NDV of claim 34, wherein theF-fusion protein either contains no amino acid residues of theectodomain of the F protein, or the F-fusion protein contains a fragmentof the ectodomain of the F protein that does not retain the activity ofthe ectodomain of the F protein.
 45. The chimeric NDV of claim 35,wherein the HN-fusion protein contains either no amino acid residues ofthe ectodomain of the HN protein, or it contains a fragment of theectodomain of the HN protein that does not retain the activity of theectodomain of the HN protein.
 46. The chimeric NDV of claim 34, whereinthe sequence that encodes the F-fusion protein is inserted between the Pand M genes of the NDV genome.
 47. The chimeric NDV of claim 35, whereinthe sequence that encodes the HN-fusion protein is inserted between theP and M genes of the NDV genome.
 48. The chimeric NDV of claim 34,wherein the chimeric NDV is attenuated.
 49. The chimeric NDV of claim35, wherein the chimeric NDV is attenuated.
 50. An immunogenicformulation comprising the chimeric NDV of claim
 48. 51. An immunogenicformulation comprising the chimeric NDV of claim 49.